Showing papers in "Journal of Food Science in 2011"

Defining the public health threat of food fraud.

Abstract: Food fraud, including the more defined subcategory of economically motivated adulteration, is a food risk that is gaining recognition and concern. Regardless of the cause of the food risk, adulteration of food is both an industry and a government responsibility. Food safety, food fraud, and food defense incidents can create adulteration of food with public health threats. Food fraud is an intentional act for economic gain, whereas a food safety incident is an unintentional act with unintentional harm, and a food defense incident is an intentional act with intentional harm. Economically motivated adulteration may be just that—economically motivated—but the food-related public health risks are often more risky than traditional food safety threats because the contaminants are unconventional. Current intervention systems are not designed to look for a near infinite number of potential contaminants. The authors developed the core concepts reported here following comprehensive research of articles and reports, expert elicitation, and an extensive peer review. The intent of this research paper is to provide a base reference document for defining food fraud—it focuses specifically on the public health threat—and to facilitate a shift in focus from intervention to prevention. This will subsequently provide a framework for future quantitative or innovative research. The fraud opportunity is deconstructed using the criminology and behavioral science applications of the crime triangle and the chemistry of the crime. The research provides a food risk matrix and identifies food fraud incident types. This project provides a starting point for future food science, food safety, and food defense research. Practical Application: Food fraud, including the more defined subcategory of economically motivated adulteration, is a food protection threat that has not been defined or holistically addressed. The terrorist attacks of September 11, 2001, led to the development of food defense as an autonomous area of study and a new food protection discipline. As economically motivated adulteration grows in scope, scale, and awareness, it is conceivable that food fraud will achieve the same status as an autonomous concept, between food safety and food defense. This research establishes a starting point for defining food fraud and identifying the public health risks.

The Role of Dietary Fiber in the Bioaccessibility and Bioavailability of Fruit and Vegetable Antioxidants

Abstract: Antioxidants are abundant compounds primarily found in fresh fruits and vegetables, and evidence for their role in the prevention of degenerative diseases is continuously emerging. However, the bioaccessibility and bioavailability of each compound differs greatly, and the most abundant antioxidants in ingested fruit are not necessarily those leading to the highest concentrations of active metabolites in target tissues. Fruit antioxidants are commonly mixed with different macromolecules such as carbohydrates, lipids, and proteins to form a food matrix. In fruits and vegetables, carbohydrates are the major compounds found, mainly in free and conjugated forms. Dietary fiber, the indigestible cell wall component of plant material, is considered to play an important role in human diet and health. Most studies on antioxidant bioavailability are focused on foods and beverages from which antioxidants are easily released. There is evidence indicating that food microstructure affects the bioaccessibility and bioavailability of several nutrients, referring mostly to antioxidants. Nevertheless, the specific role of dietary fiber in the absorption of antioxidants has not been widely discussed. In this context, the purpose of the present review is to compile and analyze evidence relating to the association between dietary fiber and antioxidants, and the physical and chemical interactions that modulate their release from the chyme in the gastrointestinal tract.

Antibacterial activity and mechanism of action of chlorogenic acid.

Abstract: In this study, the antibacterial activity and mechanism of action of chlorogenic acid against bacteria were assessed. The data from minimum inhibitory concentration (MIC) values showed that chlorogenic acid effectively inhibited the growth of all tested bacterial pathogens, and the MIC values were ranging from 20 to 80 μg/mL. An investigation into action mode of chlorogenic acid against the pathogen indicated that chlorogenic acid significantly increased the outer and plasma membrane permeability, resulting in the loss of the barrier function, even inducing slight leakage of nucleotide. The leakage of cytoplasmic contents was also observed by electron micrographs. These results supported our hypothesis that chlorogenic acid bound to the outer membrane, disrupted the membrane, exhausted the intracellular potential, and released cytoplasm macromolecules, which led to cell death.

Phenolic acid composition and antioxidant properties of Malaysian honeys.

Abstract: The phenolic acid and flavonoid contents of Malaysian Tualang, Gelam, and Borneo tropical honeys were compared to those of Manuka honey. Ferric reducing/antioxidant power assay (FRAP) and the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical-scavenging activities were also quantified. All honey extracts exhibited high phenolic contents (15.21 ± 0.51- 42.23 ± 0.64 mg/kg), flavonoid contents (11.52 ± 0.27- 25.31 ± 0.37 mg/kg), FRAP values (892.15 ± 4.97- 363.38 ± 10.57 μM Fe[II]/kg), and high IC₅₀ of DPPH radical-scavenging activities (5.24 ± 0.40- 17.51 ± 0.51 mg/mL). Total of 6 phenolic acids (gallic, syringic, benzoic, trans-cinnamic, p-coumaric, and caffeic acids) and 5 flavonoids (catechin, kaempferol, naringenin, luteolin, and apigenin) were identified. Among the Malaysian honey samples, Tualang honey had the highest contents of phenolics, and flavonoids, and DPPH radical-scavenging activities. We conclude that among Malaysian honey samples, Tualang honey is the richest in phenolic acids, and flavonoid compounds, which have strong free radical-scavenging activities.

Canola Proteins for Human Consumption: Extraction, Profile, and Functional Properties

Abstract: Canola protein isolate has been suggested as an alternative to other proteins for human food use due to a balanced amino acid profile and potential functional properties such as emulsifying, foaming, and gelling abilities. This is, therefore, a review of the studies on the utilization of canola protein in human food, comprising the extraction processes for protein isolates and fractions, the molecular character of the extracted proteins, as well as their food functional properties. A majority of studies were based on proteins extracted from the meal using alkaline solution, presumably due to its high nitrogen yield, followed by those utilizing salt extraction combined with ultrafiltration. Characteristics of canola and its predecessor rapeseed protein fractions such as nitrogen yield, molecular weight profile, isoelectric point, solubility, and thermal properties have been reported and were found to be largely related to the extraction methods. However, very little research has been carried out on the hydrophobicity and structure profiles of the protein extracts that are highly relevant to a proper understanding of food functional properties. Alkaline extracts were generally not very suitable as functional ingredients and contradictory results about many of the measured properties of canola proteins, especially their emulsification tendencies, have also been documented. Further research into improved extraction methods is recommended, as is a more systematic approach to the measurement of desired food functional properties for valid comparison between studies.

Phytochemicals and antioxidant capacities in rice brans of different color.

Abstract: Rice bran, a byproduct of the rice milling process, contains most of the phytochemicals. This study aimed at determining the concentrations of lipophilic, solvent-extractable (free), and cell wall-bound (bound) phytochemicals and their antioxidant capacities from brans of white, light brown, brown, purple, and red colors, and broccoli and blueberry for comparison. The concentrations of lipophilic antioxidants of vitamin E (tocopherol and tocotrienols) and γ-oryzanols were 319.67 to 443.73 and 3861.93 to 5911.12 μg/g bran dry weight (DW), respectively, and were not associated with bran color. The total phenolic, total flavonoid, and antioxidant capacities of ORAC (oxygen radical absorbance capacity), DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging, and iron-chelating in the free fraction were correlated with the intensity of bran color, while variations of these in the bound fraction were less than those in the free fraction among brans. Compounds in the bound fraction had higher antioxidant capacity of ORAC than DPPH, relative to those in the free fraction. The bound fraction of light-color brans contributed as much to its total ORAC as the free fraction. Total proanthocyanidin concentration was the highest in red rice bran, while total anthocyanin was highest in purple brans. The predominant anthocyanin was cyanidin-3-glucoside. Red and purple brans had several fold higher total phenolics and flavonoids as well as ORAC and DPPH, from both free and bound fractions, than freeze-dried blueberry and broccoli. These results indicate that rice brans are natural sources of hydrophilic and lipophilic phytochemicals for use in quality control of various food systems as well as for nutraceutical and functional food application.

Poly (DL-lactide-co-glycolide) (PLGA) nanoparticles with entrapped trans-cinnamaldehyde and eugenol for antimicrobial delivery applications.

Abstract: Eugenol and trans-cinnamaldehyde are natural compounds known to be highly effective antimicrobials; however, both are hydrophobic molecules, a limitation to their use within the food industry. The goal of this study was to synthesize spherical poly (DL-lactide-co-glycolide) (PLGA) nanoparticles with entrapped eugenol and trans-cinnamaldehyde for future antimicrobial delivery applications. The emulsion evaporation method was used to form the nanoparticles in the presence of poly (vinyl alcohol) (PVA) as a surfactant. The inclusion of antimicrobial compounds into the PLGA nanoparticles was accomplished in the organic phase. Synthesis was followed by ultrafiltration (performed to eliminate the excess of PVA and antimicrobial compound) and freeze-drying. The nanoparticles were characterized by their shape, size, entrapment efficiency, and antimicrobial efficiency. The entrapment efficiency for eugenol and trans-cinnamaldehyde was approximately 98% and 92%, respectively. Controlled release experiments conducted in vitro at 37 °C and 100 rpm for 72 h showed an initial burst followed by a slower rate of release of the antimicrobial entrapped inside the PLGA matrix. All loaded nanoparticles formulations proved to be efficient in inhibiting growth of Salmonella spp. (Gram-negative bacterium) and Listeria spp. (Gram-positive bacterium) with concentrations ranging from 20 to 10 mg/mL. Results suggest that the application of these antimicrobial nanoparticles in food systems may be effective at inhibiting specific pathogens. Practical Application: Nanoencapsulation of lipophilic antimicrobial compounds has great potential for improving the effectiveness and efficiency of delivery in food systems. This study consisted of synthesizing PLGA nanoparticles with entrapped eugenol and trans-cinnamaldehyde. By characterizing these new delivery systems, one can understand the controlled-release mechanism and antimicrobial efficiency that provides a foundation that will enable food manufacturers to design smart food systems for future delivery applications, including packaging and processing, capable of ensuring food safety to consumers.

Galactooligosaccharides: novel components of designer foods.

Abstract: Since introduction of functional foods, commercialization of the traditionally used probiotics has ushered in more followers into the new fraternity of sophisticated, health-conscious consumers. In 1995, this was followed by the first introduction of prebiotics. Prebiotics are defined as "a non-digestible feed supplement, beneficially affecting the host by selectively stimulating growth and/or activity in one or a limited number of bacteria in the colon." The number of new product introductions with prebiotics has steeply increased over the last few years. Paradoxically, probiotics have limited applications as these cannot be used in wide range of food products because of their viability issue. Fortunately, prebiotics do not suffer from any such constraint and can be used in a wide range of food products. Probiotics do not have a long shelf life in their active form. In most cases, refrigeration is required to maintain the shelf life. While probiotics are predominantly used in fermented dairy products, the use of prebiotics has expanded into other food categories. Prebiotics have successfully been incorporated in a wide variety of human food products such as baked goods, sweeteners, yoghurts, nutrition bars, and meal replacement shakes. For instance, the introduction of galacto-oligosaccharides (GOS) into baby foods has been very successful. GOS, which are identical to the human milk oligosaccharides, has emerged with strong clinical support for both digestive and immune health. Various aspects related to GOS such as types and functions of functional food constituents with special reference to GOS, their role as prebiotics, and enhanced industrial production through microbial intervention are dealt in this review.

Influence of biopolymer emulsifier type on formation and stability of rice bran oil-in-water emulsions: whey protein, gum arabic, and modified starch.

Abstract: Rice bran oil (RBO) is used in foods, cosmetics, and pharmaceuticals due to its desirable health, flavor, and functional attributes. We investigated the effects of biopolymer emulsifier type and environmental stresses on the stability of RBO emulsions. Oil-in-water emulsions (5% RBO, 10 mM citrate buffer) stabilized by whey protein isolate (WPI), gum arabic (GA), or modified starch (MS) were prepared using high-pressure homogenization. The new MS used had a higher number of octenyl succinic anhydride (OSA) groups per starch molecule than conventional MS. The droplet diameters produced by WPI and MS were considerably smaller (d 1000 nm). The influence of pH (3 to 8), ionic strength (0 to 500 mM NaCl), and thermal treatment (30 to 90 °C) on the physical stability of the emulsions was examined. Extensive droplet aggregation occurred in WPI-stabilized emulsions around their isoelectric point (4 200 mM, pH 7), and at high temperatures (>70 °C, pH 7, 150 mM NaCl), which was attributed to changes in electrostatic and hydrophobic interactions between droplets. There was little effect of pH, ionic strength, and temperature on emulsions stabilized by GA or MS, which was attributed to strong steric stabilization. In summary: WPI produced small droplets at low concentrations, but they had poor stability to environmental stress; GA produced large droplets and needed high concentrations, but they had good stability to stress; new MS produced small droplets at low concentrations, with good stability to stress. Practical Application: This study showed that stable rice bran oil-in-water emulsions can be formed using biopolymer emulsifiers. These emulsions could be used to incorporate RBO into a wide range of food products. We compared the relative performance of whey protein, GA, and a new MS at forming and stabilizing the emulsions. The new OSA MS was capable of forming small stable droplets at relatively low concentrations.

A brief review of the occurrence, use, and safety of food-related nanomaterials.

Abstract: Nanotechnology and nanomaterials have tremendous potential to enhance the food supply through novel applications, including nutrient and bioactive absorption and delivery systems; ingredient functionality; improved colors and flavors; microbial, allergen, and contaminant detection and control; and food packaging properties and performance. To determine the current state of knowledge regarding the safety of these potential uses of nanomaterials, an appraisal of the published literature on the safety of food-related nanomaterials was undertaken. A method of assessment of reliability of toxicology studies was developed to conduct this appraisal. The review of the toxicology literature on oral exposure to food-related nanomaterials found that the number of studies is limited. Exposure to nanomaterials in the human food chain may occur not only through intentional uses in food manufacturing, but also via uses in agricultural production and carry over from use in other industries. Although a number of analytical methods are useful in physicochemical characterization of manufactured nanomaterials, new methods may be needed to more fully detect and characterize nanomaterials incorporated into foods and in other media. There is a need for additional toxicology studies of sufficient quality and duration on different types of nanomaterials to further our understanding of the characteristics of nanomaterials that affect safety of oral exposure resulting from use in various food applications.

The role of oral processing in dynamic sensory perception.

Abstract: Food oral processing is not only important for the ingestion and digestion of food, but also plays an important role in the perception of texture and flavor. This overall sensory perception is dynamic and occurs during all stages of oral processing. However, the relationships between oral operations and sensory perception are not yet fully understood. This article reviews recent progress and research findings on oral food processing, with a focus on the dynamic character of sensory perception of solid foods. The reviewed studies are discussed in terms of both physiology and food properties, and cover first bite, mastication, and swallowing. Little is known about the dynamics of texture and flavor perception during mastication and the importance on overall perception. Novel approaches use time intensity and temporal dominance techniques, and these will be valuable tools for future research on the dynamics of texture and flavor perception.

Potential risks resulting from fruit/vegetable-drug interactions: effects on drug-metabolizing enzymes and drug transporters.

Abstract: It has been well established that complex mixtures of phytochemicals in fruits and vegetables can be beneficial for human health. Moreover, it is becoming increasingly apparent that phytochemicals can influence the pharmacological activity of drugs by modifying their absorption characteristics through interactions with drug transporters as well as drug-metabolizing enzyme systems. Such effects are more likely to occur in the intestine and liver, where high concentrations of phytochemicals may occur. Alterations in cytochrome P450 and other enzyme activities may influence the fate of drugs subject to extensive first-pass metabolism. Although numerous studies of nutrient-drug interactions have been published and systematic reviews and meta-analyses of these studies are available, no generalizations on the effect of nutrient-drug interactions on drug bioavailability are currently available. Several publications have highlighted the unintended consequences of the combined use of nutrients and drugs. Many phytochemicals have been shown to have pharmacokinetic interactions with drugs. The present review is limited to commonly consumed fruits and vegetables with significant beneficial effects as nutrients and components in folk medicine. Here, we discuss the phytochemistry and pharmacokinetic interactions of the following fruit and vegetables: grapefruit, orange, tangerine, grapes, cranberry, pomegranate, mango, guava, black raspberry, black mulberry, apple, broccoli, cauliflower, watercress, spinach, tomato, carrot, and avocado. We conclude that our knowledge of the potential risk of nutrient-drug interactions is still limited. Therefore, efforts to elucidate potential risks resulting from food-drug interactions should be intensified in order to prevent undesired and harmful clinical consequences.

Antioxidant capacities of phenolic compounds and tocopherols from Tunisian pomegranate (Punica granatum) fruits.

Abstract: This article aims to determine the phenolic, tocopherol contents, and antioxidant capacities from fruits (juices, peels, and seed oils) of 6 Tunisian pomegranate ecotypes. Total anthocyanins were determined by a differential pH method. Hydrolyzable tannins were determined with potassium iodate. The tocopherol (α-tocopherol, γ-tocopherol, and δ-tocopherol) contents were, respectively, 165.77, 107.38, and 27.29 mg/100 g from dry seed. Four phenolic compounds were identified and quantified in pomegranate peel and pulp using the high-performance liquid chromatography/ultraviolet method: 2 hydroxybenzoic acids (gallic and ellagic acids) and 2 hydroxycinnamic acids (caffeic and p-coumaric acids). Juice, peel, and seed oil antioxidants were confirmed by ferric reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC) methods. The highest values were recorded in peels with 25.63 mmol trolox equivalent/100 g and 22.08 mmol TE/100 g for FRAP and ORAC assay, respectively. Results showed that the antioxidant potency of pomegranate extracts was correlated with their phenolic compound content. In particular, the highest correlation was reported in peels. High correlations were also found between peel hydroxybenzoic acids and FRAP ORAC antioxidant capacities. Identified tocopherols seem to contribute in major part to the antioxidant activity of seed oil. The results implied that bioactive compounds from the peel might be potential resources for the development of antioxidant function dietary food.

Essential Oils and Their Principal Constituents as Antimicrobial Agents for Synthetic Packaging Films

Abstract: Spices and herbal plant species have been recognized to possess a broad spectrum of active constituents that exhibit antimicrobial (AM) activity. These active compounds are produced as secondary metabolites associated with the volatile essential oil (EO) fraction of these plants. A wide range of AM agents derived from EOs have the potential to be used in AM packaging systems which is one of the promising forms of active packaging systems aimed at protecting food products from microbial contamination. Many studies have evaluated the AM activity of synthetic AM and/or natural AM agents incorporated into packaging materials and have demonstrated effective AM activity by controlling the growth of microorganisms. This review examines the more common synthetic and natural AM agents incorporated into or coated onto synthetic packaging films for AM packaging applications. The focus is on the widely studied herb varieties including basil, oregano, and thyme and their EOs.

Antimicrobial Effectiveness of Bioactive Packaging Materials from Edible Chitosan and Casein Polymers: Assessment on Carrot, Cheese, and Salami

Abstract: Antimicrobial packaging is one of the most promising active packaging systems for controlling spoilage and pathogenic microorganisms. In this work, the intrinsic antimicrobial properties of chitosan (CH) were combined with the excellent thermoplastic and film-forming properties of sodium caseinate (SC) to prepare SC/CH film-forming solutions and films. The antimicrobial effectiveness of SC, CH, and SC/CH coatings on the native microfloras of cheese, salami, and carrots was evaluated. In vitro assays through the test tube assay indicated that the most significant antimicrobial effect was achieved by CH and SC/CH solutions on carrot and cheese native microfloras. SC film-forming solutions did not exert antimicrobial activity on any of the native microflora studied. SC, CH, and SC/CH films stored in controlled environments showed that the retention of the antimicrobial action was observed until 5-d storage, at 65% relative humidity in both temperatures (10 °C and 20 °C). In vivo assays were also performed with SC, CH, and SC/CH applied as coatings or wrappers on the 3 food substrates. CH and SC/CH applied at both immersion and wrapper exerted a significant bactericidal action on mesophilic, psychrotrophic, and yeasts and molds counts, showing the 3 microbial populations analyzed a significant reduction (2.0 to 4.5 log CFU/g). An improvement of the bactericidal properties of the CH/SC blend respect to those of the neat CH film is reported. The ionic interaction between both macromolecules enhances its antimicrobial properties. Practical Application: The continuous consumer interest in high quality and food safety, combined with environmental concerns has stimulated the development and study of biodegradable coatings that avoid the use of synthetic materials. Among them, edible coatings, obtained from generally recognized as safe (GRAS) materials, have the potential to reduce weight loss, respiration rate, and improve food appearance and integrity. They can be used in combination with other food preservation techniques in order to extend the effectiveness of the food preservation chain. Moreover, antimicrobial films and coatings have innovated the concept of active packaging and have been developed to reduce, inhibit, or delay the growth of microorganisms on the surface of food in contact with the package. The use of antimicrobials packaging films to control the growth of microorganisms in food can have a significant impact on shelf-life extension and food safety. In addition, antimicrobial films can be prepared by the combination of inherent antimicrobial materials (that is, CH), with good film-forming protein-based ones (that is, SC). Therefore, the objective of this work is to study the performance of 2 biodegradable and edible biopolymers and their combination as natural packages for selected food products.

Pomological features, nutritional quality, polyphenol content analysis, and antioxidant properties of domesticated and 3 wild ecotype forms of raspberries (Rubus idaeus L.).

Abstract: The raspberry (Rubus idaeus L.) is an economically important berry crop that contains many phenolic compounds with potential health benefits. In this study, important pomological features, including nutrient content and antioxidant properties, of a domesticated and 3 wild (Yayla, Yavuzlar, and Yedigol) raspberry fruits were evaluated. Also, the amount of total phenolics and flavonoids in lyophilized aqueous extracts of domesticated and wild ecotypes of raspberry fruits were calculated as gallic acid equivalents (GAEs) and quercetin equivalents (QE). The highest phenolic compounds were found in wild Yayla ecotype (26.66 ± 3.26 GAE/mg extract). Whilst, the highest flavonoids were determined in wild Yedigol ecotype (6.09 ± 1.21 QA/mg extract). The antioxidant activity of lyophilized aqueous extracts of domesticated and wild ecotypes of raspberry fruits were investigated as trolox equivalents using different in vitro assays including DPPH(•), ABTS(•+), DMPD(•+), and O(•-)(2) radical scavenging activities, H(2)O(2) scavenging activity, ferric (Fe(3+)) and cupric ions (Cu(2+)) reducing abilities, ferrous ions (Fe(2+)) chelating activity. In addition, quantitative amounts of caffeic acid, ferulic acid, syringic acid, ellagic acid, quercetin, α-tocopherol, pyrogallol, p-hydroxybenzoic acid, vanillin, p-coumaric acid, gallic acid, and ascorbic acid in lyophilized aqueous extracts of domesticated and wild ecotypes of raspberry fruits were detected by high-performance liquid chromatography and tandem mass spectrometry (LC-MS-MS). The results clearly show that p-coumaric acid is the main phenolic acid responsible for the antioxidant and radical scavenging activity of lyophilized aqueous extracts of domesticated and wild ecotypes of raspberry fruits.

Comparative Antioxidant Activity of Edible Japanese Brown Seaweeds

Abstract: Japanese edible brown seaweeds, Eisenia bicyclis (Arame), Kjellmaniella crassifolia (Gagome), Alaria crassifolia (Chigaiso), Sargassum horneri (Akamoku), and Cystoseira hakodatensis (Uganomoku) were assayed for total phenolic content (TPC), fucoxanthin content, radical scavenging activities (DPPH, peroxyl radical, ABTS, and nitric oxide), and antioxidant activity in a liposome system. Among the solvents used for extraction, methanol was the most effective to extract total phenolics (TPC) from brown seaweeds. Among 5 kinds of brown seaweeds analyzed, methanol extract from C. hakodatensis was the best source for antioxidants. The high antioxidant activity of the extract was based not only on the high content of phenolics, but on the presence of fucoxanthin. No significant correlation (P > 0.05) was observed between TPC per gram extract with DPPH radical scavenging activity of the methanol extracts. These observed discrepancy would be due to structural variations in the phenolic compounds, and different levels of fucoxanthin in the extracts. The present study also demonstrated the synergy in the antioxidant activity of the combination of brown seaweed phenolics and fucoxanthin.

Use of Organic Acids to Inactivate Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes on Organic Fresh Apples and Lettuce

Abstract: This study was undertaken to investigate the antimicrobial effect of organic acids against Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes on whole red organic apples and lettuce. Several studies have been conducted to evaluate organic acids as sanitizers. However, no studies have compared antimicrobial effects of various organic acids on organic fresh produce, including evaluation of color changes of produce. Apples and lettuce were inoculated with a cocktail of 3 strains each of 3 foodborne pathogens provided above and treated with 1% and 2% organic acids (propionic, acetic, lactic, malic, and citric acid) for 0, 0.5, 1, 5, and 10 min. With increasing treatment time and acid concentration, organic acid treatments showed significant reduction compared to the control treatment (distilled water), and differences in antimicrobial effects between organic acids were observed. After 10 min of treatment with 1% and 2% organic acids in apples, propionic (0.92 to 2.75 log reduction), acetic (0.52 to 2.78 log reduction), lactic (1.69 to >3.42 log reduction), malic (1.48 to >3.42 log reduction), and citric acid (1.52 to >3.42 log reduction) exhibited significant (P < 0.05) antibacterial effects against 3 foodborne pathogens compared to the control treatment. In lettuce, propionic (0.93 to 1.52 log reduction), acetic (1.13 to 1.74 log reduction), lactic (1.87 to 2.54 log reduction), malic (2.32 to 2.98 log reduction), and citric acid (1.85 to 2.86 log reduction) showed significant (P < 0.05) effects compared to the control treatment. Changes in sample color subjected to organic acids treatment were not significant during storage. Practical Application: It is suggested that organic acids have a potential as sanitizers for organic fresh produce. These data may help the organic produce industry provide safe fresh produce for consumers.

Oregano: Chemical Analysis and Evaluation of Its Antimalarial, Antioxidant, and Cytotoxic Activities

Abstract: GC-FID and GC-MS analysis of essential oil from oregano leaves (Origanum compactum) resulted in the identification of 46 compounds, representing more than 98% of the total composition. Carvacrol was the predominant compound (36.46%), followed by thymol (29.74%) and p-cymene (24.31%). Serial extractions with petroleum ether, ethyl acetate, ethanol, and water were performed on aerials parts of Origanum compactum. In these extracts, different chemical families were characterized: polyphenols (gallic acid equivalent 21.2 to 858.3 g/kg), tannins (catechin equivalent 12.4 to 510.3 g/kg), anthocyanins (cyanidin equivalent 0.38 to 5.63 mg/kg), and flavonoids (quercetin equivalent 14.5 to 54.7 g/kg). The samples (essential oil and extracts) were subjected to a screening for antioxidant (DPPH and ABTS assays) and antimalarial activities and against human breast cancer cells. The essential oil showed a higher antioxidant activity with an IC50= 2 ± 0.1 mg/L. Among the extracts, the aqueous extract had the highest antioxidant activity with an IC50= 4.8 ± 0.2 mg/L (DPPH assay). Concerning antimalarial activity, Origanum compactum essential oil and ethyl acetate extract showed the best results with an IC50 of 34 and 33 mg/mL, respectively. In addition, ethyl acetate extract (30 mg/L) and ethanol extract (56 mg/L) showed activity against human breast cancer cells (MCF7). The oregano essential oil was considered to be nontoxic.

Preparation and characterization of agar/clay nanocomposite films: the effect of clay type.

Abstract: Agar-based nanocomposite films with different types of nanoclays, such as Cloisite Na+, Cloisite 30B, and Cloisite 20A, were prepared using a solvent casting method, and their tensile, water vapor barrier, and antimicrobial properties were tested. Tensile strength (TS), elongation at break (E), and water vapor permeability (WVP) of control agar film were 29.7 ± 1.7 MPa, 45.3 ± 9.6%, and (2.22 ± 0.19) × 10−9 g·m/m2·s·Pa, respectively. All the film properties tested, including transmittance, tensile properties, WVP, and X-ray diffraction patterns, indicated that Cloisite Na+ was the most compatible with agar matrix. TS of the nanocomposite films prepared with 5% Cloisite Na+ increased by 18%, while WVP of the nanocomposite films decreased by 24% through nanoclay compounding. Among the agar/clay nanocomposite films tested, only agar/Cloisite 30B nanocomposite film showed a bacteriostatic function against Listeria monocytogenes.

Antioxidant and Antidiabetic Properties of Condensed Tannins in Acetonic Extract of Selected Raw and Processed Indigenous Food Ingredients from Kenya

Abstract: Recently, tannins have received considerable attention as health-promoting component in various plant foods and several studies have reported on its nutraceutical properties. However, no study has established the role of condensed tannins in indigenous foods of Kenya. Therefore, this study was designed to evaluate the antioxidant activity (DPPH and FRAP) and antidiabetic effects (α-amylase and α-glucosidase inhibition activities) of condensed tannins in some selected raw and traditionally processed indigenous cereals, legumes, oil seeds, and vegetables. The condensed tannin content of the grains and vegetables ranged between 2.55 and 4.35 g/100 g DM and 1.53 and 5.73 g/100 g DM, respectively. The scavenging effect of acetonic extract on DPPH radical ranged from 77% to 90% while the reducing power was found to be 31 to 574 mmol Fe(II)/g DM in all the investigated food ingredients. The condensed tannin extracts of the analyzed samples showed promising antidiabetic effects with potential α-amylase and α-glucosidase inhibition activities of 23% to 44% and 58% to 88%, respectively. Condensed tannins extracted from the amaranth grain, finger millet, field bean, sunflower seeds, drumstick, and amaranth leaves exerted significantly higher antioxidant and antidiabetic activities than other food ingredients. Among the traditional processing methods, roasting of grains and cooking of vegetables were found to be more suitable mild treatments for preserving the tannin compound and its functional properties as opposed to soaking + cooking and blanching treatments. The identified elite sources of optimally processed indigenous food ingredients with promising results could be used as health-promoting ingredients through formulation of therapeutic diets.

In Vitro Batch Fecal Fermentation Comparison of Gas and Short-Chain Fatty Acid Production Using “Slowly Fermentable” Dietary Fibers

Abstract: Sustained colonic fermentation supplies beneficial fermentative by-products to the distal colon, which is particularly prone to intestinal ailments. Blunted/delayed initial fermentation may also lead to less bloating. Previously, we reported that starch-entrapped alginate-based microspheres act as a slowly fermenting dietary fiber. This material was used in the present study to provide a benchmark to compare to other “slowly fermentable” fibers. Dietary fibers with previous reports of slow fermentation, namely, long-chain inulin, psyllium, alkali-soluble corn bran arabinoxylan, and long-chain β-glucan, as well as starch-entrapped microspheres were subjected to in vitro upper gastrointestinal digestion and human fecal fermentation and measured over 48 h for pH, gas, and short-chain fatty acids (SCFA). The resistant fraction of cooked and cooled potato starch was used as another form of fermentable starch and fructooligosaccharides (FOS) served as a fast fermenting control. Corn bran arabinoxylan and long-chain β-glucan initially appeared slower fermenting with comparatively low gas and SCFA production, but later fermented rapidly with little remaining in the final half of the fermentation period. Long-chain inulin and psyllium had slow and moderate, but incomplete, fermentation. The resistant fraction of cooked and cooled potato starch fermented rapidly and appeared similar to FOS. In conclusion, compared to the benchmark slowly fermentable starch-entrapped microspheres, a number of the purported slowly fermentable fibers fermented fairly rapidly overall and, of this group, only the starch-entrapped microspheres appreciably fermented in the second half of the fermentation period. Practical Application: Consumption of dietary fibers, particularly commercial prebiotics, leads to uncomfortable feelings of bloating and flatulence due to their rapid degradation in our large intestine. This article employs claimed potential slowly fermenting fibers and compares their fermentation rates with a benchmark slow fermenting fiber that we fabricated in an in vitro simulation of the human digestive system. Results show a variety of fermentation profiles only some of which have slow and extended rate of fermentation.

Bactericidal action of binary and ternary mixtures of carvacrol, thymol, and eugenol against Listeria innocua.

Abstract: The bactericidal effect of 3 natural agents (carvacrol, thymol, and eugenol) was evaluated as well as their binary and ternary mixtures on Listeria innocua inactivation in liquid model systems. Minimal bactericidal concentrations (MBC) of these agents were determined, and then binary and ternary mixtures were evaluated. Culture media were inoculated with L. innocua and incubated for 72 h at 35 °C. Turbidity of studied systems were determined every 24 h. The most effective individual antimicrobial agent was carvacrol, followed by thymol and then eugenol with MBCs of 150, 250, and 450 mg kg(-1), respectively. It was observed that the most effective binary mixture was 75 mg kg(-1) carvacrol and 62.5 mg kg(-1) thymol. Furthermore, the ternary mixture carvacrol-thymol-eugenol in concentrations of 75, 31.25, and 56.25 mg kg(-1), correspondingly, was the most effective for L. innocua inactivation. Several binary and ternary mixtures of these 3 natural antimicrobial agents worked adequately to inactivate L. innocua.

Effect of cassava starch coating on quality and shelf life of fresh-cut pineapple (Ananas comosus L. Merril cv "Pérola").

Abstract: This research studied the influence of treatment with ascorbic acid, citric acid, and calcium lactate dipping and cassava starch edible coatings on quality parameters and shelf life of fresh-cut pineapple in slices during 12 d at 5 °C. After previous tests, the treatments selected for this study were samples dipped into antibrowning solution with 0.5% of ascorbic acid and 1% of citric acid, with and without 2% of calcium lactate and coated with 2% of cassava starch suspensions. Changes in weight loss, juice leakage, mechanical properties (stress at failure), color parameters (L* and H*), ascorbic acid content, sensory acceptance, and microbial growth of fruits were evaluated. Samples only treated with antibrowning agents were used as control. Edible coatings with and without calcium lactate were efficient in reducing weight loss, juice leakage, and maintaining firmness during storage. However, these samples showed more browning and the ascorbic acid content was reduced. All treatments presented good sensory acceptance (scores above 6). The determining factor of shelf life of pineapple slices was the microbial spoilage. A shelf life of 8 d was obtained for pineapple slices only treated with antibrowning agents. On the other hand, coated samples showed a reduced shelf life of 7 d and higher yeast and mold growth. Thus, although cassava starch coatings were efficient in reducing respiration rate, weight loss, and juice leakage and maintained mechanical properties, these treatments were not able to increase the shelf life of minimally processed pineapple. Practical Application: Pineapple fruit is highly appreciated for its aroma, flavor, and juiciness, but its immediate consumption is difficult. Therefore, pineapple is a potential fruit for minimal processing. However, shelf life of fresh-cut pineapple is very limited by changes in color, texture, appearance, off-flavors, and microbial growth. The use of edible coatings as gas and water vapor barrier and antibrowning agents can extend the storage time and maintain the quality of fresh-cut produce. Cassava starch and alginate coatings are alternative to preserve minimally processed pineapples without changing the quality parameters of fresh fruit. Thus, this study is useful for consumers and fresh-cut industry interested in knowing factors affecting shelf life and quality of fresh-cut pineapple.

Effect of Oryzanol and Ferulic Acid on the Glucose Metabolism of Mice Fed with a High‐Fat Diet

Abstract: The effects of oryzanol and ferulic acid on the glucose metabolism of high-fat-fed mice were investigated. Male C57BL/6N mice were randomly divided into 4 groups: NC group fed with normal control diet; HF group fed with high-fat (17%) diet; HF-O group fed with high-fat diet supplemented with 0.5% oryzanol; and HF-FA group fed with high-fat diet supplemented with 0.5% ferulic acid. All animals were allowed free access to the experimental diets and water for 7 wk. At the end of the experimental period, the HF-O and HF-FA groups exhibited significantly lower blood glucose level and glucose-6-phosphatase (G6pase) and phosphoenolpyruvate carboxykinase (PEPCK) activities, and higher glycogen and insulin concentrations and glucokinase (GK) activity compared with NC and HF groups. The results of this study illustrate that both oryzanol and ferulic acid could reduce the risk of high-fat diet-induced hyperglycemia via regulation of insulin secretion and hepatic glucose-regulating enzyme activities.

Antifungal activity of 2 lactic acid bacteria of the Weissella genus isolated from food.

Abstract: In the present study, a total of 116 lactic acid bacteria (LAB) strains isolated from Mill flour and fermented cassava were screened for their antifungal activity. Three strains among 116 were selected for their strongest inhibitory activity against food molds. These 3 strains were Lactobacillus plantarum VE56, Weissella cibaria FMF4B16, and W. paramesenteroides LC11. The compounds responsible for the antifungal activity were investigated. The strains displayed an inhibitory activity against targeted molds at acidic pH. However, the influence of organic acids was rejected according to the calculated minimal inhibitory concentration (MIC). Antifungal compounds were investigated in the cell-free supernatants and phenyllactic acid (PLA) was detected in different amounts with a maximal concentration for Lb. plantarum VE56 (0.56 mM). Hydroxy fatty acid, such as 2-hydroxy-4-methylpentanoic acid, was also produced and involved in the inhibitory activity of Lb. plantarum VE56 and W. paramesenteroides LC11. Antifungal LAB are known to produce PLA and 3-hydroxy fatty acids and other organic acids with antifungal activity. This short communication focuses on antifungal activity from Weissella genus. The antifungal activity was attributed to antifungal compounds identified such as PLA, 2-hydroxy-4-methylpentanoic acid, and other organic acids. Nevertheless, the concentration produced in the cell-free supernatant was too low to compare to their MIC, suggesting that the inhibitory activity was caused by a synergy of these different compounds. Practical Application: Antifungal LAB are interesting to prevent food spoilage in fermented food and prolong their shelf life. In this way, chemical preservatives could be avoided and replaced by natural preservatives.

Changes in Volatile Compounds of Peanut Oil during the Roasting Process for Production of Aromatic Roasted Peanut Oil

Abstract: The changes in volatile compounds composition of peanut oil during the roasting process of aromatic roasted peanut oil (ARPO) production were investigated. The analyses were performed by gas chromatography-mass spectrometry combined with headspace solid phase microextraction (HS-SPME/GC-MS). Among the volatiles identified in ARPO, the N-heterocyclic chemical class possessed the highest relative percentage area (RPA) 61.68%, followed by O-heterocyclic group with an RPA of 24.57%. Twenty pyrazines were considered to be the key contributors to the intense nutty/roasty flavor typical of ARPO. Compounds that increased significantly in concentration during the roasting process were mainly Maillard reaction products, as well as compounds derived from Strecker degradation and lipid peroxidation. The results clearly showed that the roasting process was necessary to obtain the typical nutty/roasty aroma of ARPO. Practical Application: ARPO is the traditional edible oil in China that possesses a characteristic strong nutty and roasty flavor that distinguishes it from other edible vegetable oils. During the production, the roasting process is the crucial factor for the formation of the typical roasted peanut aroma that plays an important role in sensory quality of peanut oil. In our investigation, not only the volatile changes of peanut oil pressed from relevant peanut seeds roasted at different roasting time were determined, but also the contributions of identified volatiles on the typical nutty/roasty flavor of ARPO were discussed. Our work clearly demonstrated the significant effect of roasting process on the typical flavor formation of ARPO. The results are valuable as scientific guidance for the roasting process that better satisfy demands of the peanut oil industries for better flavor.

Physicochemical and phytochemical properties of cold and hot water extraction from Hibiscus sabdariffa.

Abstract: Hibiscus cold (25 °C) and hot (90 °C) water extracts were prepared in various time–temperature combinations to determine equivalent extraction conditions regarding their physicochemical and phytochemical properties. Equivalent anthocyanins concentration was obtained at 25 °C for 240 min and 90 °C for 16 min. Total phenolics were better extracted with hot water that also resulted in a higher antioxidant capacity in these extracts. Similar polyphenolic profiles were observed between fresh and dried hibiscus extracts. Hibiscus acid and 2 derivatives were found in all extracts. Hydroxybenzoic acids, caffeoylquinic acids, flavonols, and anthocyanins constituted the polyphenolic compounds identified in hibiscus extracts. Two major anthocyanins were found in both cold and hot extracts: delphynidin-3-sambubioside and cyanidin-3-sambubioside. In general, both cold and hot extractions yielded similar phytochemical properties; however, under cold extraction, color degradation was significantly lower and extraction times were 15-fold longer. Practical Application: Hibiscus beverages are prepared from fresh or dried calyces by a hot extraction and pasteurized, which can change organoleptic, nutritional, and color attributes. Nonthermal technologies such as dense phase carbon dioxide may maintain their fresh-like color, flavor, and nutrients. This research compares the physicochemical and phytochemical changes resulting from a cold and hot extraction of fresh and dried hibiscus calyces and adds to the knowledge of work done on color, quality attributes, and antioxidant capacity of unique tropical products. In addition, the research shows how these changes could lead to alternative nonthermal processes for hibiscus.

Volatile composition of pomegranates from 9 Spanish cultivars using headspace solid phase microextraction.

Abstract: Fruits of 9 Spanish pomegranate cultivars were analyzed for quality parameters, volatile composition, and sensory profile. Volatile compounds were extracted using headspace solid phase micro-extraction (HS-SPME) and analyzed by gas chromatography-mass spectrometry (GC-MS) and flame ionization detector (GC-FID). Twenty-one compounds were found in the headspace of fresh pomegranate juices, including aldehydes, monoterpenes, and alcohols. The most abundant compounds were hexanal, limonene, trans-2-hexenal, and cis-3-hexenol. Fruits from the cultivars Mollar Elche(ME) ME14, ME1, and ME2 presented the highest values of overall liking by the consumer panel; however, their total volatiles concentration were low compared to the other pomegranate cultivars and their color intensity was intermediate. Overall consumer liking of pomegranate juices was mainly associated with the presence of monoterpenes (α-terpineol); however, high aldehydes (trans-2-hexenal) concentrations were correlated with poor overall consumer liking. Fruits from sour-sweet cultivars (PTO7 and ADO4) could improve the quality of ME pomegranate juices due to their intense color, high monoterpenes concentrations, and their moderate sourness. Practical Application: The information provided in this study proves that sour-sweet pomegranate fruits can be used in the manufacturing of pomegranate juices and will improve the sensory quality and the volatile composition of this product.

Physical and antibacterial properties of edible films formulated with apple skin polyphenols.

Abstract: Fruit and vegetable skins have polyphenolic compounds, terpenes, and phenols with antimicrobial and antioxidant activity. These flavoring plant essential oil components are generally regarded as safe. Edible films made from fruits or vegetables containing apple skin polyphenols have the potential to be used commercially to protect food against contamination by pathogenic bacteria. The main objective of this study was to evaluate physical properties as well as antimicrobial activities against Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella enterica of apple skin polyphenols at 0% to 10% (w/w) concentrations in apple puree film-forming solutions formulated into edible films. Commercial apple skin polyphenol powder had a water activity of 0.44 and high total soluble phenolic compounds and antioxidant capacity (995.3 mg chlorogenic acid/100 g and 14.4 mg Trolox/g, respectively). Antimicrobial activities of edible film containing apple skin polyphenols were determined by the overlay method. Apple edible film with apple skin polyphenols was highly effective against L. monocytogenes. The minimum concentration need to inactive L. monocytogenes was 1.5%. However, apple skin polyphenols did not show any antimicrobial effect against E. coli O157:H7 and S. enterica even at 10% level. The presence of apple skin polyphenols reduced water vapor permeability of films. Apple skin polyphenols increased elongation of films and darkened the color of films. The results of the present study show that apple skin polyphenols can be used to prepare apple-based antimicrobial edible films with good physical properties for food applications by direct contact.