Showing papers in "Lwt - Food Science and Technology in 2019"

Rheological and mechanical behavior of milk protein composite gel for extrusion-based 3D food printing

Abstract: To characterize the rheological and mechanical properties of soft matter for 3D food printing, a milk protein composite gel was prepared by dispersing milk protein concentrate (MPC) into sodium caseinate solution and then its rheological and textural properties were analyzed. The results showed that the milk protein gel containing 400–450 g/L of total protein had the best printing performance, matched the model best and had good fidelity. The low-field nuclear magnetic resonance and frequency sweep data suggested that the inner structure of the protein gel gradually transformed from a tangled state to a three-dimensional structure with increasing total protein content, which is beneficial for 3D printing. The apparent viscosity, thixotropy, and yield stress also increased with the total protein content. Thus, rheology could be used to evaluate the applicability of soft materials for extrusion-based 3D printing. This study provides a potential reference for evaluating other gel-like materials for 3D printing.

Development of a novel colorimetric food package label for monitoring lean pork freshness

Abstract: The aim of this work was to develop an easy-to-use food package label for pork shelf-life assessment. Meat samples were packaged in polyethylene terephthalate trays with on-package indicator labels and kept at 5 °C for 8 days. These indicators contained three groups of pH-sensitive dyes, i.e., bromocresol purple, bromothymol blue, and a mixture of bromothymol blue and methyl red. Results of pH, total volatile basic nitrogen (TVB-N) contents, aerobic plate counts and sensory scores of pork differentiated between fresh (on 0–3 days), medium fresh (on 4–5 days), and spoiled lean pork (on 6–8 days). Results of total color difference and principal components analysis carried out with colorimetric data of different indicator labels showed that the indicator label made by a mixture of bromothymol blue and methyl red at 3:2 proportion (at an initial pH of 5.0) was able to discriminate fresh (red), medium fresh (goldenrod), and spoiled (green) pork in cold storage. The statistical models obtained by partial least squares, with the color change of label, successfully predicted TVB-N contents and aerobic plate counts of pork. These results suggest the potential feasibility of this particular indicator system for monitoring freshness of packaged pork via color change detected directly using the naked eye.

Improving 3D printing process of lemon juice gel based on fluid flow numerical simulation

Abstract: Food 3D printing has received attention as a novel field in recent years, bringing new ideas and opportunities for the development and transformation of food processing technology. This work investigated the moisture and rheological properties of lemon juice gels with different starches by experimental studies and simulated the effect of different material properties and process parameters (material viscosity and relaxation time, inlet volume flow rate and nozzle diameter) on the velocity, shear rate and pressure fields in the flow channel by the POLYFLOW software. Results showed that with the addition of different kinds of starches, the viscosity and mechanical properties of the lemon juice gel were varied. Adding potato starch altered fluidity with different relative degree of bound or immobilized water of lemon juice gel. According to the simulation study, in the same shape of the flow path, the velocity and shear velocity fields were determined by the inlet volume flow rate. The change of different process parameters was found to cause changes in pressure field in the flow channel to varying degrees, and the change of the nozzle diameter had the greatest influence on the pressure distribution. In addition, the extruded material exhibited swelling phenomenon.

Ultrasound assisted extraction of bioactive compounds from pomegranate (Punica granatum L.) peel

Abstract: Ultrasound-assisted extraction (UAE) technology was used for extracting effective components from pomegranate (Punica granatum L.variety SisheKape-Ferdos) peel (POP). A response surface method was used to investigate the effects of independent process variables (ultrasonic amplitude (power control, UA): 20, 60 and 100%, and ultrasonic exposure time (UET): 5, 10 and 15 min) on the yield (Y) and antioxidant characteristics: total phenolic compounds (TPC), 1,1-diphenyl-2-picrylhydrazyl free radical scavenging (DPPH), ferric reducing-antioxidant power (FRAP), half maximal of radical-scavenging activity (IC50) of aqueous pomegranate peel extract. According to Derringer's desired function approach, the optimal conditions based on both individual and combinations of all process variables were UA 60% and UET 6.2 min, and at this optimum condition, the predicted maximum values of Y, TPC, DPPH, FRAP, and IC50 of the pomegranate peel extract (POPx) were 13.1%, 42.2 mg GA/g, 88.8%, 1824.6 μmol Fe2+/g, and 0.51 mg/mL, respectively. The experimental values were in a good agreement with the predicted values. Also, at optimal conditions, the minimum inhibitory concentration (MIC) of the extract (mean diameter of inhibition zone: 17.7 mm) showed that it had antifungal activities against Aspergillus niger.

Antibacterial and anti-biofilm activities of peppermint essential oil against Staphylococcus aureus

Abstract: Peppermint essential oil (PEO) has been reported to prevent microbial growth and prolong the shelf-life of food, but there are few studies about its possible antibacterial mechanism and anti-biofilm activity against Staphylococcus aureus (S. aureus). In this study, the antibacterial mechanism of PEO on planktonic S. aureus was investigated by determining electrical conductivity, cell membrane integrity, cell viability, and bacterial morphology. Moreover, a crystal violet quantification assay and plate colony counts were used to evaluate the effects of PEO on inhibiting and inactivating S. aureus biofilms. The results show that PEO affected the permeability and integrity of the S. aureus cell membrane, as evidenced by the increase in relative electrical conductivity and leakage of nucleic acids, proteins, and ATP. Decreased cell viability and changes in cell morphology further confirmed the cell membrane damage to S. aureus by PEO. In addition, PEO significantly inhibited the formation of biofilm, and inactivated mature biofilm formed by S. aureus. These findings suggest that PEO has the potential to control planktonic S. aureus and its biofilm in food processing environments.

Antibacterial and antioxidant properties of hydroxypropyl methylcellulose-based active composite films incorporating oregano essential oil nanoemulsions

Abstract: Hydroxypropyl methylcellulose (HPMC) was combined with oregano essential oil nanoemulsion (ORNE) at concentrations of 0–7.5% (v/v) to produce active composite films. The mechanical, optical, water vapour barrier, antimicrobial, and antioxidant properties of the composite films were evaluated. The composite films containing 5.0% (v/v) ORNE showed increased elongation at break compared to the control films, although their tensile strength and Young's modulus were lower. In addition, these composite films showed greater opacity and decreased UV and water vapour transmittance, indicating that incorporation of ORNE resulted in enhanced barrier properties. Furthermore, the composite films were effective against all tested bacterial strains, particularly against Salmonella typhimurium, as evidenced by the large inhibition zone attained (47.5 mm) in the disc diffusion test. Antioxidant activity was assessed by the DPPH and ABTS assays, with the composite films containing 5.0% (v/v) ORNE showing values approximately 69% and 46% higher than those of the control, respectively. Therefore, the developed composite films could potentially be used as active packaging with antibacterial and antioxidant properties.

High-intensity ultrasound processing of kiwifruit juice: Effects on the ascorbic acid, total phenolics, flavonoids and antioxidant capacity

Abstract: The objective of the study was to investigate the effect of high-intensity ultrasound processing (0, 4, 8, 12 and 16 min at 400 W, 25 kHz frequency) on the total phenolics, flavonoids, ascorbic acid, and antioxidant capacity of kiwifruit juice. The microstructural characteristics of treated kiwifruit samples were also measured. The results reveal that the total phenolics, flavonoids and antioxidant capacity of treated samples (16 min) significantly increased by 108.65%, 105.56%, and 65.67%, respectively compared to the control group. However, 16-min ultrasound treatment significantly decreased the total protein and ascorbic acid in kiwifruit juice. Microstructure measurement states the formation of microscopic channels or holes, cell walls rupture, torn and tissue distortion after ultrasound processing, which reveals the physical mechanism of ultrasound treatment in improving the extraction of bioactive molecules. These findings indicate that high-intensity ultrasound has an enormous potential to increase these bioactive molecules and antioxidants capacity of kiwifruit samples.

Effect of roasting treatment on the chemical composition of sesame oil

Abstract: Sesame oil is rich in highly concentrated bioactive components including tocopherols, phytosterols and lignans (e.g., sesamolin, sesamin, and sesamol). The chemical composition and quantification of oil extracted from roasted sesame seeds was investigated and compared with unroasted sesame oil in relation to health-promoting and potentially harmful substances (particularly polycyclic aromatic hydrocarbons, abbreviated as PAHs). With roasting, the peroxide value and color development of oils was elevated obviously while the total tocopherols and sesamolin decreased steadily. The acid values in the current experiment were expected to grow as the roasting time increased at the same temperature, and the acid value decreased in the first 30 min of roasting at 160 °C. Increased roasting temperature or time facilitates sesamol formation in sesame oil. The fatty acid profiles are almost independent of roasting conditions. There was a significant increase in PAHs with elevated temperatures and extended times. In general, favorable sensory qualities accompanied by a beneficial healthy composition of sesame oil may be attributed to the treatment by roasting at a temperature from 160 °C to 180 °C and a roasting time of less than 20 min.

A starch edible surface coating delays banana fruit ripening

Abstract: A rice starch edible coating blended with sucrose esters was developed for controlling the postharvest physiological activity of Cavendish banana to extend postharvest quality during ripening at 20 ± 2 °C. Coating effectiveness was assessed against changes in fruit physiochemical parameters such as weight loss, titratable acidity, total soluble solids, flesh fruit firmness, ion leakage, colour change, respiration, ethylene production, chlorophyll degradation and starch conversion were determined. The topography of coating material on the fruit surface was evaluated by scanning electron microscope (SEM). Surface morphology studies highlighted the binding compatibility of the coating matrix with the fruit peel character and formed a continuous uniform layer over the fruit surface. The results showed that the coating was effective in delaying ethylene biosynthesis and reducing respiration rate. Other factors impacting included delayed chlorophyll degradation, reduced weight loss and retention of fruit firmness for the first six days, all of which improved the commercial value of the fruit. The shelf life of coated fruit was prolonged for 12 days in comparison with the untreated control which ripened within seven days and lost marketability after Day 6. The pilot study demonstrates the effectiveness of a starch-based edible coating formulation for improving the ambient storage capacity of banana fruit.

FTIR-ATR determination of protein content to evaluate whey protein concentrate adulteration

Abstract: We evaluated the potential application of Fourier-Transformed Infrared spectroscopy using Attenuated Total Reflectance (FTIR-ATR) to characterize and detect adulteration of whey protein concentrate (WPC). Samples were adulterated by substituting WPC by milk whey powder (MWP). Principal Component Analysis (PCA) was used to characterize the spectra. Partial Least Squares (PLS) regressions were applied to model and predict the protein content and the amount in grams of WPC and MWP in the samples. In WPC, Amide I and II bands showed decreasing trend with the protein content of the samples. The carbohydrate region between 1160 and 1000 cm−1 showed spectra with opposite behavior of the Amide bands, evincing the ν C O peak (1030 cm−1) that increases as MWP was added. In PCA, PC1 (64.5%) and PC2 (18.8%) described above 80% of total variance of the spectra. PC1 variance was most influenced by Amide I, II and carbohydrate regions. In all cases, PLS showed low prediction errors, high precision and coefficients of determination of the global fit above 0.99. Therefore, the association of FTIR-ATR spectroscopy with multivariate approaches revealed strong potential to detect adulteration in nutritional supplements and high accuracy to predict simultaneously the protein content and mass of WPC and MWP added.

Effect of inlet air temperature and gum Arabic concentration on encapsulation of probiotics by spray drying

Abstract: Encapsulation of probiotics using food grade polymers as wall material can be a good alternative for the development of any probiotic food. The current study details about the effect of processing conditions on physico-chemical and flow properties of microencapsulated probiotic powder by spray drying. Maltodextrin and gum Arabic (GA) are used as wall material where 20% MD is kept constant. Varied concentration of GA (0, 2.5, 5, 7.5 and 10%) with respect to total solid content and inlet air temperature (130, 140 and 150 °C) was chosen as independent variables to produce the spray dried probiotic powder. The moisture content, water activity, and encapsulation efficiency of probiotic powder was in the range of 4.59–9.05% (w.b.), 0.52 to 0.33, and 65–89.15%, respectively. The loose bulk density, tapped density, true density, porosity and color L∗ ranged from 0.47 to 0.53 g/cm3, 0.56–0.68 g/cm3, 0.6–1.06 g/cm3 0.17–0.55, and 91.35–95.68, respectively. The handling properties i.e., flowability was “possible” and “fair” according to Hausner ratio and Carr's index values.

Effect of different drying methods on the sensory quality and chemical components of black tea

Abstract: This study investigated the effects of conventional hot-air drying, microwave drying, far-infrared drying, halogen lamp drying and halogen lamp-microwave combination drying on sensory and chemical quality of black tea Sensory evaluation revealed that the black tea dried with halogen lamp-microwave and microwave got more uniform black color, fresher taste and higher sweet aroma Total quality score was in the order: halogen lamp-microwave dried tea (893) > microwave dried tea (882) > halogen lamp dried tea (864) > far-infrared dried tea (852) > hot-air dried tea (831) The highest contents of polyphenols, catechins and theaflavins were found when black tea dried with microwave Far-infrared drying and hot-air drying could remarkably increase the contents of amino acids and soluble sugars The volatiles of black tea were identified with gas chromatography-mass spectrometry Microwave dried black tea got the maximum contents of volatile compounds, followed by halogen lamp-microwave dried tea, far-infrared dried tea, halogen lamp dried tea and hot-air dried tea Overall, microwave drying and halogen lamp-microwave drying could ameliorate the drying process of black tea

Reducing the glycemic index of short dough biscuits by using apple pomace as a functional ingredient

Abstract: The present research aimed at enriching short dough biscuits with apple pomace to reduce their glycemic index. Apple pomace produced on a laboratory scale was dehydrated and milled to a powder, which was characterized for soluble and insoluble dietary fiber, and for phenolic content. Apple pomace was used to partially replace wheat flour (10 and 20% w/w) in biscuits, which were characterized for their sensory properties and submitted to in vitro digestion to predict the glycemic index. Results indicated that apple pomace contained impressive amounts of dietary fiber (nearly 40%), mainly represented by insoluble fiber (more than 25%). Apple pomace led to a significant reduction in the expected glycemic index of reformulated biscuits. The conventional biscuit presented a glycemic index of 70 and was thus classified as high glycemic index food. Substituting wheat flour by 10 and 20% with apple pomace reduced biscuit glycemic index to 65 and 60 respectively, thus ranking the product within the intermediate glycemic index foods. Using industrial apple pomace led to analogous results, demonstrating that this by-product could be exploited to reduce the glycemic index of bakery foods, thus concomitantly satisfying the need for strategies to manage type 2 diabetes and to valorize food by-products.

Effect of hydrocolloid addition on dimensional stability in post-processing of 3D printable cookie dough

Abstract: This paper provides a solution to the problem of the deformation of 3D printed cookie products during post-processing such as baking. The influence of the incorporation of hydrocolloids on the dimensional stability of the cookie dough during temperature variations was investigated. Methylcellulose and xanthan gum were blended in mass fractions of 0.5, 1, 2, and 3 g/100 g dough basis. In dynamic viscoelasticity experiments, during the temperature sweep, the cookie doughs with methylcellulose showed losses in storage modulus (G′) and loss modulus (G″) that were comparable to those of the control samples. Although the incorporated xanthan gum exhibited high structural retention owing to its high shear modulus, its low extrudability resulted in a high extrusion hardness and poor 3D printing performance. In the post-processing, sufficient dimensional stability was observed even with a xanthan gum incorporation of 0.5 g/100 g. Moreover, the heat-resistant 3D printable cookie samples with 0.5 g/100 g xanthan gum exhibited a texture profile having a hardness and fracturability similar to those of the control cookies.

Moringa extract enhances the fermentative, textural, and bioactive properties of yogurt

Abstract: Yogurt is a fermented dairy food produced by lactic acid bacteria (LAB). Moringa oleifera is known for its bioactive properties. The aim of this study was to evaluate the effects of moringa on the fermentation, quality characteristics, and bioactive properties of yogurt. Yogurt was supplemented with 0–0.2% moringa extract (ME; hot water extract, 100 °C, 30 min) and fermented using mixed starter cultures (Streptococcus thermophilus, Lactobacillus acidophilus, and Bifidobacterium longum). Addition of ME to yogurt significantly accelerated the rate of fermentation by promoting growth of LAB. ME reduced syneresis up to 21% and enhanced the water-holding capacity by 17%. The viscosity of 0.2% ME yogurt was approximately 5-fold higher than control yogurt and radical-scavenging activity of ME yogurt increased up to 40% in a dose-dependent manner during the 21 days of cold storage. Sensory testing showed that the addition of 0.05% ME to yogurt did not negatively influence the overall acceptability of the product, compared to the control. The addition of ME to yogurt decreased the oxidative stress and increased the expression of antioxidant proteins in human colon cells. Thus, ME-fermented yogurt maintains the sensory acceptability and exerts positive health benefits because of increased LAB proliferation and enhanced antioxidant properties.

Willingness to consume insect-containing foods: A survey in the United States

Abstract: Entomophagy, consuming insect as food, is a rising topic in western societies due to its positive attributes on the environment, food security, and nutrition. However, this practice has not established popularity in the United States (US). The purpose of this study is to identify the factors that affect willingness to consume insect-containing foods (ICF) in the US. A questionnaire consisting of 26 questions regarding demographics, exposure, knowledge, and willingness to consume ICF was developed and administered to Survey Monkey (n = 397). ANOVA and independent t-test were performed using SPSS. Results suggested that participants were more willing to consume ICF if they were familiar with the concept, were aware of the benefits of entomophagy, or had tried ICF prior to this study (p

Ultrasound-assisted immersion freezing accelerates the freezing process and improves the quality of common carp (Cyprinus carpio) at different power levels

Abstract: This study evaluated the effect of ultrasound-assisted immersion freezing (UIF) on the freezing speed and quality of common carp (Cyprinus carpio) at different ultrasonic power levels. The results revealed that UIF increased the speed of freezing, with UIF at 175 W (UIF-175) being optimal. Compared to refrigerator freezing and immersion freezing, UIF samples had less thawing and cooking loss. Microstructural observation showed that UIF-175 reduced pore diameter and ice crystal size. As ultrasonic power increased, the L*-value first decreased and then increased (P 0.05). UIF-175 samples exhibited the shortest T21 and T22 relaxation time, which indicated that this appropriate ultrasonic power level reduced the mobility of free and immobilized water. Therefore, UIF at appropriate ultrasonic power significantly decreased the freezing time of fish samples and improved the fish meat quality.

Quality evaluation and drying kinetics of shitake mushrooms dried by hot air, infrared and intermittent microwave–assisted drying methods

Abstract: The aim of the study was to conduct comparative analyses on drying kinetics, color, rehydration ratio, polysaccharide content and aromatic components composition of shitake mushrooms dried by using hot air drying, infrared drying and intermittent microwave assisted hot air drying. Intermittent microwave–assisted drying resulted in greatly reduced drying time and higher drying rate in comparison with the other methods. The highest polysaccharide content (240.28 mg/100 g) was achieved when microwave–assisted drying was used. Furthermore, microwave–assisted drying showed its predominance in the categories and amount of generated nitric aroma (1.17%) during drying, and it could be a method for improving fresh–like characteristics of dried vegetables due to the moderate level of aldehydes (0.26%) and ketones (4.22%) formed during drying. Shitake mushrooms treated with hot air drying showed the greatest amount of sulfuric aromatic compounds (7.7%) and the highest rehydration ability as well as a lower total color difference in the cap. Therefore, shitake mushrooms dried by hot air or combined with microwave should be considered due to their enhanced physical properties or chemical components.

Eggplant peel as a high potential source of high methylated pectin: Ultrasonic extraction optimization and characterization

Abstract: Eggplant peel as a new source was used for pectin extraction using ultrasonic method. The extraction process factors were optimized using Box-Behnken design (BBD) and under optimal conditions (ultrasound power of 50 W, irradiation time of 30 min and pH of 1.5), the predicted extraction yield (35.36 g/100 g) was validated by the experimental results (33.64 ± 1.12 g/100 g). The eggplant peel pectin (EPP) was examined in terms of chemical, physicochemical, functional and structural features. The results indicated that the EPP was rich in galacturonic acid (66.08g/100 g), high in degree of esterification (61.22%) and total phenolic content, and low in ash and protein content. Also, EPP had a suitable value of water and oil holding capacity, emulsifying properties, antioxidant activity, and foam capacity. In addition, FT-IR and 1H NMR spectroscopy proved the existence of pectin structure in the obtained samples and XRD pattern suggested a high crystallinity in EPP.

Fruit peels waste for the green synthesis of silver nanoparticles with antimicrobial activity against foodborne pathogens

Abstract: In this work we report an eco-friendly and low cost method for reducing and capping silver nanoparticles with a lyophilized extract from grape and orange wastes. The synthesis of silver nanoparticles (AgNPs) was monitored by UV–Vis spectroscopy and their characterization was carried out using Transmission Electron Microscopy (TEM), Diffuse Reflectance Infrared Spectroscopy (DRIFT) and X Ray Diffraction (XRD). The AgNPs were crystalline and spherical, with diameters from 3 to 14 nm and 5–50 nm for the nanoparticles obtained from the grape and orange extract, respectively. DRIFT spectroscopy suggested the involvement of various functional groups from extract secondary metabolites during nanoparticle synthesis and capping nanoparticles. The antimicrobial activity of AgNPs was tested against Escherichia coli O157:H7 and Listeria monocytogenes using the agar diffusion method and optical density (OD600). Non-significant difference of L. monocytogenes growth inhibition was observed between AgNPs obtained from both extracts, demonstrating a 13.5 mm diameter growth inhibition at 100 μg/ml. For E. coli O157:H7, only the AgNPs obtained from the grape extract exhibited a dose-dependent antimicrobial activity showing a final OD of 0.42 at 100 μL.

Antifungal activity and mechanism of citral, limonene and eugenol against Zygosaccharomyces rouxii

Abstract: The aim of this study was to investigate the antifungal activity and mechanisms of citral, limonene and eugenol against Zygosaccharomyces rouxii. All the three essential oil ingredients presented strong antifungal activities against Z. rouxii. Minimum inhibitory concentrations of citral, limonene and eugenol were 0.188, 0.75 and 0.4 μL/mL, and the minimum fungicidal concentrations were 0.375, 3 and 0.8 μL/mL, respectively. Scanning electron microscopy showed that the tested essential oil compounds had destructive effects on the yeast cell surface. After treated by citral, limonene and eugenol, the relative electric conductivity and leakage of nucleic acid were increased significantly. SDS-PAGE analysis indicated that the essential oil components could result in the loss of soluble proteins and might also destroy the yeast protein or inhibit their expression. These results demonstrated that citral, limonene and eugenol exerted their antifungal action against Z. rouxii through cell membrane damage and destruction of cellular proteins. This study provided a theoretical possibility that citral, limonene and eugenol could be used as natural food preservatives for the control of Z. rouxii-related spoilage in the fruit juice industry.

Flavor characteristics of shrimp sauces with different fermentation and storage time

Abstract: The present study investigated the volatile compounds in nearly three-year shrimp sauces and the effects of different fermentation and storage time on the integral aroma characteristics. The 89 volatile compounds were identified by solid phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS) analysis. Compared with the other two samples, the shrimp sauces which fermented and storage for 2 years has the highest umami amino acid content and the better flavor. The results of electronic nose (e-nose) and electronic tongue (e-tongue) detection to distinguish the aroma characteristics of different samples demonstrated good agreement with those obtained by GC-MS analysis. These results suggested that proper fermentation and storage time are critical to the flavor quality of shrimp sauces.

Evaluation of water dynamics and protein changes in bigeye tuna (Thunnus obesus) during cold storage

Abstract: The objective of this study was to investigate water dynamics and protein changes in bigeye tuna (Thunnus obesus) stored at 0 °C and 4 °C for up to 6 days The values of various protein parameters (trichloroacetic acid (TCA)-soluble peptide content, Ca2+-ATPase enzyme activity and total -SH content) decreased with increasing storage time Fourier transform infrared spectra indicated that the secondary structure of the proteins changed; the contents of α-helixes and β-turns significantly decreased, while that of β-sheets significantly increased (p

Protective effects of α-casein or β-casein on the stability and antioxidant capacity of blueberry anthocyanins and their interaction mechanism

Abstract: The impacts of α-casein or β-casein on the stability and antioxidant ability of blueberry anthocyanins were investigated and they exhibited remarkable outcomes. β-casein is a little more effective than α-casein. To detect the protective mechanism, the binding of α-casein or β-casein with malvidin -3-o-galactoside (M3G), the major monomer in blueberry anthocyanins, was examined by fluorescence and ultraviolet–visible absorption spectroscopy. Results showed that the binding of α-casein or β-casein with M3G would lead to static quenching and their binding forces were Van der Waals forces and hydrogen bonding. CD spectroscopy presented structure alterations in α-casein and β-casein after interacting with M3G. Moreover, molecular modeling displayed the conformation of casein-M3G complexes. The findings outlined in the current study showed that α-casein or β-casein could encapsulate M3G through binding with it, which formed the basis for the promoting effects of α-casein or β-casein on the stability and antioxidant ability of blueberry anthocyanins.

Bee bread as a functional product: Chemical composition and bioactive properties

Abstract: Bee bread is a mixture of pollen pellets, honey and lactic acid bacteria, and the basis of food in the hive. In the present study, a Moroccan bee bread has been analyzed concerning the palynological analysis, nutritional value and chemical composition (free sugars, organic acids, mineral composition, fatty acid, tocopherols and polyphenols); in vitro antioxidant activity and antimicrobial activity screened against pathogenic bacteria and fungi were also evaluated. The studied bee bread was a good source of protein (19.96 ± 0.08 g/100 g), total free sugars (18 ± 1 g/100 g), macroelements and microelements content, revealed high levels of polyunsaturated fatty acids (64.7 ± 0.4%), tocopherols (10.9 ± 0.9 mg/100 g) and natural antioxidants, such as flavonol glycoside derivatives, being isorhamnetin-O-hexosyl-O-rutinoside the major phenolic compound present. The bee bread showed antioxidant activity and effectiveness against all the bacteria and fungi tested. This work contributes to the chemical and bioactive knowledge of this unexplored natural product.

Fluorescence spectroscopy as a rapid and non-destructive method for monitoring quality and authenticity of fish and meat products: Impact of different preservation conditions

Abstract: Fish and meat are highly perishable food products, requiring both proper technologies for quality preservation and rapid methods for analysis. From a technological point of view, several preservation methods have been applied to extend shelf life of fish and meat products while from an analytical perspective, fluorescence spectroscopy has been extensively used to investigate its potential as a rapid and non-destructive technique compared to traditional analytical methods. In this review, the most commonly applied techniques to preserve the quality of fish and meat products are first presented. The main methods used to assess both quality and authenticity of such products are then discussed. A special focus is placed on the fluorescence spectroscopy as a highly sensitive and selective techniques compared to other spectroscopic techniques. Moreover, attention has been paid to the effect of different preservation methods on the fluorescence measurements of fish and meat products. Finally, certain limitations are discussed, and some recommendations are suggested for future studies.

Au@Ag nanostructure based SERS substrate for simultaneous determination of pesticides residue in tea via solid phase extraction coupled multivariate calibration

Abstract: The study aimed to extend the applications of surface-enhanced Raman scattering (SERS) – recently one of the most promising and widely employed technique in food safety and quality monitoring – towards determination of two analytes in a single step for the first time. Thus, an ultra-sensitive and selective SERS based detection platform for the simultaneous determination of pesticides namely acetamiprid (AC) and 2,4-dichlorophenoxyacetic acid (2,4-D) in matcha tea has been developed. Owing to the potential interference of different nutrients and pigments in complicated matrices, the matcha tea samples with and without spiking AC and 2,4-D, were percolated through a solid phase extraction cartridge. The eluate was introduced to the SERS Au@Ag nanostructure substrate for monitoring SERS signal with subsequent chemometrics modeling. Under the optimized experimental conditions, a linear calibration exhibited at GA-PLS model with RPD values of 6.53 and 6.23, and Rp values 0.9943 and 0.9923, respectively for AC and 2,4-D. The method was validated in both mixed and single spiking conditions successfully in terms of student's t- and F test at 95% confidence with satisfactory recovery percentages. An RSD value

Determination of the microbial community in Amazonian cocoa bean fermentation by Illumina-based metagenomic sequencing

Abstract: High-throughput DNA sequencing (HTS) was used to investigate the microbial community of cocoa bean spontaneous fermentation in the Amazon biome. The characterization was described in three localities from Para state (Amazon biome) and one locality from Bahia state, the top Brazilian state for cocoa production, for comparison of the microbial community structure. The microbial community profile was determined through a metagenomics approach using the Illumina HiSeq platform. Our data showed that the microbial community is composed of a consortium consisting of yeast (i.e., Pichia and Candida), filamentous fungi (i.e., Aspergillus, Penicillium and Fusarium), lactic acid bacteria (i.e., Leuconostoc, Lactococcus, and Lactobacillus), acetic acid bacteria (i.e., Acetobacter and Gluconobacter), enterobacteria and bacilli. Interestingly, Acetobacter pasteurianus was found in higher relative abundance than expected, and three acetic acid bacteria species were identified for the first time in cocoa fermentation (i.e., Komagataeibacter hansenii, Roseomonas sp. and Acidisphaera sp.). Some microorganisms were only detected in Amazonian cocoa and not detected in Bahia cocoa, including six yeast species (i.e., Starmerella bacillaris, Candida temnochilae, Zygosaccharomyces bailii, Candida glabrata, Saccharomycopsis crataegensis and Saccharomycopsis amapae) and seven lactic acid bacteria (i.e., Lactococcus lactis, Fructobacillus pseudoficulneus, Weissella confusa, Pediococcus pentosaceus, Lactobacillus reuteri, Lactobacillus murinus and Lactobacillus pontis). This study provides the first description of the microbiome in cocoa fermentation from the Amazon region, and these data open new perspectives for exploring these microorganisms in biotechnology applications, as well as their use as a starter culture to obtain high-quality cocoa beans.

Characterization and antibacterial activity evaluation of curcumin loaded konjac glucomannan and zein nanofibril films

Abstract: The exploration of methods to produce biodegradable and bioactive nanofibril films is of great scientific and technological interests. We reported a strategy to constructing of nanofibril films by using konjac glucomannan (KGM) and zein via electrospinning technology. The characterization of the nanofibril films was conducted via Scanning electron microscopy (SEM), Thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and water contact angle measurements. The interactions of hydrogen bonds between KGM and zein were confirmed, and the addition of zein caused an increase of thermal properties and hydrophobicity. The morphology and size of nanofibers significantly depended on zein contents. We further loaded curcumin (Cur), a natural polyphenolic compound, within the KGM/Zein/Cur nanofibril films to investigate the antibacterial and antioxidating properties for the novel nanofibril films. In comparison with a pure KGM and zein film, KGM/Zein/Cur nanofibril films indicated an excellent antibacterial activity against food-borne pathogens. Our work suggested that the KGM/Zein/Cur nanofibril films had a potential application in food packaging, which opens a facile pathway to the modification of KGM-based biopolymer to form nanofilms.

Cold plasma treatment induces phenolic accumulation and enhances antioxidant activity in fresh-cut pitaya (Hylocereus undatus) fruit

Abstract: Non-thermal cold plasma as a novel method for maintaining safety and inducing phenolic accumulation in fresh-cut pitaya (Hylocereus undatus) fruit and the possible mechanisms were investigated. Results showed that cold plasma treatment (60 kV for 5 min) significantly inhibited the growth of total aerobic bacterial counts, increased the cutting-induced phenolic accumulation and enhanced antioxidant activity in fresh-cut pitaya fruit. Moreover, cold plasma treatment promoted the consumption of main sugars, enhanced the level of energy status, accelerated the generation of reactive oxygen species (ROS) at earlier storage, increased gene expression and activity of crucial enzymes in phenylpropanoid pathway. The present research provides convincing evidence regarding the beneficial effects of cold plasma treatment for inducing phenolic accumulation and enhancing antioxidant activity of fresh-cut pitaya fruit and offers potential opportunity for the processing and preservation of fresh-cut fruits and vegetables.