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Showing papers in "Lwt - Food Science and Technology in 2021"


Journal ArticleDOI
TL;DR: In this paper, different flexible protein molecules are obtained after ultrasound treatment at different power conditions (0, 200, 400, and 600) and the structural and functional changes in the soybean protein isolate (SPI) are determined.
Abstract: The structure and physicochemical properties of a protein have significant effects on its molecular flexibility. Herein, different flexible protein molecules are obtained after ultrasound treatment at different power conditions (0, 200, 400, and 600 W), and the structural and functional changes in the soybean protein isolate (SPI) are determined. The correlation between flexibility (F), surface hydrophobicity (H0), and emulsifying properties is established. It is demonstrated that ultrasound decreases the α-helical content and increases the β-sheet content of the SPI, thereby increasing its flexibility and sulfhydryl content, and unfolding its tertiary structure. The SPI affords the best solubility, turbidity, surface hydrophobicity, emulsifying activity (EA), and emulsifying stability (ES) when subjected to an ultrasound power of 400 W. The correlation coefficients between flexibility and emulsification performance (0.938 (F:EA) and 0.958 (F:ES)) are significantly higher than those between the surface hydrophobicity and emulsification performance (0.772 (H0:EA) and 0.883 (H0:ES)). Therefore, the conformational flexibility of SPI, rather than its surface hydrophobicity, determines its emulsification properties. These findings provide a theoretical basis for understanding the emulsification mechanism of ultrasound-modified proteins, which is important in the food industry.

105 citations


Journal ArticleDOI
TL;DR: In this paper, four cucumber juices were prepared and evaluated, as supplemented with the ethanolic extracts of cinnamon, mint, ginger, and clove, respectively as compared to control and non-supplemented cucumber juice.
Abstract: This study aimed to produce a palatable functional cucumber juice: non-supplemented cucumber juice, control juice (J-con), and supplemented with different herbal extracts. Four juices were prepared and evaluated, as supplemented with the ethanolic extracts of cinnamon, mint, ginger, and clove denoting as; J-cin, J-min, J-gin, and J-clov, respectively as compared to J-con. HPLC analysis indicated that J-clov followed by J-min were the richest juices in the phenolic and flavonoid compounds compared to control. Pyrogallol, catechin, gallic, and chlorogenic acid were the most prominent phenolics in J-clov, while hesperidin and apigenin-6-arabinose were the most abundant flavonoids. Clove extract showed the highest (p ≤ 0.05) antioxidant activity (80%), followed by the mint extract. Clove and mint extracts significantly reduced the growth of the tested bacteria and fungi. The antioxidant activities in all juices significantly (p ≤ 0.05) decreased during the storage period (0, 2, 4, and 6 months) at 25 °C as polyphenols and flavonoids content declined. The pH and vitamin C significantly decreased; however, the titratable acidity increased. Clove and mint extracts (p ≤ 0.05) reduced the decay of total sugars by reducing the microbial load. J-clov showed the highest sensorial taste and flavor scores; however, J-min and J-cin were the best colors.

72 citations


Journal ArticleDOI
TL;DR: In this article, the thyme essential oil (TEO) was loaded in electrospinning porous poly(lactic acid) (PLA) nanofibers and coated with poly(vinyl alcohol)/poly(ethylene glycol) (PVA/PEG) blends for humidity-controlled TEO release.
Abstract: The objective of this work is to explore a new pathway to develop active packaging materials. Currently, controlled release materials have attracted considerable attention in food packaging applications. In this study, the thyme essential oil (TEO) was loaded in electrospinning porous poly(lactic acid) (PLA) nanofibers and coated with poly(vinyl alcohol)/poly(ethylene glycol) (PVA/PEG) blends for humidity-controlled TEO release. The images of scanning electron microscope displayed uniform pores distributed on the surface of PLA nanofibers. Water contact angle measurement indicated that PVA/PEG coating provided the packaging film with excellent hydrophilicity. ATR-FTIR spectral analysis supported the chemical composition of the films. The antibacterial activities of PLA/TEO/PVA/PEG films against Escherichia coli and Staphylococcus aureus reached >99%. Furthermore, the weight loss and firmness of strawberries packaged with this novel film were evaluated. Finally, the in vitro release behaviors of TEO were evaluated and the results demonstrated that the release rate could be controlled by adjusting the humidity (20% RH to 80% RH).

71 citations


Journal ArticleDOI
TL;DR: The functional characteristics of bioactive compounds, the nutritional characteristics and the results obtained after application of the above stated food processing techniques have been properly discussed in this article.
Abstract: Faba beans (Vicia faba L.) are the third most important legume after soya (Glycine max) and pea (Pisum sativum). Similar to other legumes, it contains high amount of lysine rich protein (one of the essential amino acids), carbohydrates and other essential micronutrients. It can also be entitled as the cheapest source of protein. Although, comparatively it has a higher shelf life, but this legume is highly underutilized due to the omnipresence of antinutritional factors (ANF's) like protease inhibitors, amylase inhibitors, lectins, convicine and vicine, etc. Though, the amino acid profile is not complete, but other foods such as cereals and legumes can be used as complementary to each other. Due to presence of these ANF's, harmful effects are observed after its raw ingestion, overshadowing the nutritional aspects. Recent advancements in food technology like extrusion, microwave heating, fortification, extrusion, fermentation, bioprocessing, etc. along with traditional methods have given positive results, allowing human consumption and inclusion of faba beans in various novel food products. The functional characteristics of bioactive compounds, the nutritional characteristics and the results obtained after application of the above stated food processing techniques have been properly discussed in this article.

70 citations


Journal ArticleDOI
TL;DR: In this paper, the authors investigated the influence of chitosan-pullulan (50:50) composite edible coating enrich with pomegranate peel extract on quality and storage life of green bell pepper at room (23 −± 3 −C, RH: 40 −45%) and cold (4 −± −3 −C, RH: 90 −95%) temperatures for 18 days.
Abstract: The present study was carried out to investigate the influence of chitosan-pullulan (50:50) composite edible coating enrich with pomegranate peel extract on quality and storage life of green bell pepper at room (23 ± 3 °C, RH: 40–45%) and cold (4 ± 3 °C, RH: 90–95%) temperatures for 18 days. Physiochemical characteristics as well as the quality of the bell peppers were improved by coating treatment at both the storage temperatures. Results revealed that chitosan-pullulan (50:50) composite edible coating exhibited significantly reduced physiological loss in weight & color browning, maintained total soluble solids, titratable acidity and pH. The treatment also helps to maintain phenolic content, flavonoid content, antioxidant activity, firmness, and sensorial attributes of bell pepper over the storage period. The sensory scores (freshness, color, taste, hardness) were recorded higher in treated bell-pepper during the storage period at both storage temperatures. Therefore, results of the present study suggested that composite coating of green bell pepper with chitosan-pullulan (50:50) enrich with pomegranate peel extract can maintain postharvest storage quality of bell pepper at room and cold storage temperature during storage.

64 citations


Journal ArticleDOI
TL;DR: In this article, the effects of four types of thermal processing methods (microwaving, roasting, steaming, and boiling) on the aroma profiles of acidity regulator-treated tilapia muscles were analyzed.
Abstract: Volatile organic compounds (VOCs) significantly impact food aroma. In this work, Electron nose (E-nose), headspace solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS), and headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) techniques were applied to analyze the effects of four types of thermal processing methods (microwaving, roasting, steaming, and boiling) on the aroma profiles of acidity regulator-treated tilapia muscles. E-nose analysis suggested the aroma differences could be detected by meatal oxide semiconductors of P30/2, P30/1, and PA/2. HS-SPME-GC-MS and HS-GC-IMS identified 43 VOCs (seven aldehydes, two ketones, five alcohols, one ester, twenty-two hydrocarbons, six other compounds) and 20 VOCs (four alcohols, nine aldehydes, six ketones, and one S-containing compound), respectively, in the raw and thermal processed tilapia muscles. Moreover, all these techniques demonstrated that thermal processing significantly and differently decreased the types of VOCs in the tilapia muscles. This work can provide useful knowledges for understanding the flavors of foods such as aquatic products and meats.

63 citations


Journal ArticleDOI
TL;DR: In this article, the authors evaluated the effect of different sugar smoking times on the flavour profiles of chicken drumsticks using an electronic nose (E-nose), electronic tongue (Etongue), and headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME/GC-MS).
Abstract: This study evaluated the effect of different sugar smoking times on the flavour profiles of chicken drumsticks using an electronic nose (E-nose), electronic tongue (E-tongue), and headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME/GC-MS). The moisture content, water activity, pH, and L*-value decreased from 71.26% to 65.23%, 0.987 to 0.979, 6.66 to 5.36, and 61.84 to 52.34, respectively (P 1 were detected. Principal component analysis of E-nose, E-tongue, and HS-SPME/GC-MS indicated that 3-, 4-, and 5-min smoking samples had similar odour and taste profiles. Sensory analysis indicated that the 4-min sample had increased overall acceptability. The correlation analysis of E-nose and key volatile compounds with odour activity value > 1 and VIP >1 confirmed that W1C, W3C, and W5C sensors were sensitive to aromatic compounds, and W2S sensor was sensitive to ketones. These results may provide guidance for smoked chicken producers to reasonably control flavour formation.

62 citations


Journal ArticleDOI
TL;DR: In this article, the effects of ultrasound with different powers (0-500 W) on the structure and stability of protein from sea cucumber gonad were investigated, according to the changes in phenylalanine (Phe), α-helix, β-sheet, tryptophan (Trp), surface hydrophobicity, particle size distribution, microstructure and amino acid (AA).
Abstract: The effects of ultrasound with different powers (0-500 W) on the structure and stability of protein from sea cucumber gonad were investigated, according to the changes in phenylalanine (Phe), α-helix, β-sheet, tryptophan (Trp), surface hydrophobicity, particle size distribution, microstructure and amino acid (AA). With the increase in ultrasound power, the contents of Phe, β-sheet and Trp, surface hydrophobicity and particle size first increased and then decreased, while α-helix content was opposite. Compared with the non-ultrasound group, the content of α-helix and random coil significantly decreased by 24.71% and 22.33% in the 200 W ultrasound group, while Phe content, β-sheet content, fluorescence intensity (FI), the surface hydrophobicity and hydrophobic AA significantly increased by 12.77%, 75.91%, 7.90%, 15.61% and 7.00%, respectively (P

62 citations


Journal ArticleDOI
Mi Li1, Hang Yu1, Yunfei Xie1, Yahui Guo1, Yuliang Cheng1, He Qian1, Weirong Yao1 
TL;DR: In this article, an annealing treatment was used to improve the adhesion of the active layer onto the poly (lactic acid) film, and the results showed that eugenol could be efficiently encapsulated in nanofibers (92.72 g/100 g).
Abstract: The aim of this work was to develop a novel degradable bioactive film with poly (lactic acid), gelatin and eugenol, and electrospinning technology was used to develop an active internal layer for the active films to encapsulate eugenol. An annealing treatment was used to improve the adhesion of the active layer onto the poly (lactic acid) film. The results showed that eugenol could be efficiently encapsulated in nanofibers (92.72 g/100 g). The internal active layer containing it showed a uniform fiber morphology observed by scanning electron microscope. The diameter of nanofibers was enlarged and the hydrophobicity was enhanced, the antioxidant activity and antibacterial activity were improved as the addition of eugenol compared with pure gelatin nanofibers. In particular, nanofibers containing 4 μL/mL eugenol (G3) showed the highest antioxidant activity (32.99 mg DPPH/g dry weight), radical scavenging activity (43.80%), and significant microbial growth inhibition with CFU of about 3 log units (E. coli) and 2.5 log units (S. aureus) lower than the control. In conclusion, our results suggested that active layer could be an effective method to encapsulate eugenol, and the poly (lactic acid)/gelatin nanofibers bilayer film was a novel biodegradable packaging material with excellent antioxidant activity and antibacterial activity.

57 citations


Journal ArticleDOI
TL;DR: In this article, carvacrol was incorporated in poly(lactic acid) (PLA) and poly(butylene adipate terephthalate) (PBAT) blends at different polymer proportions (30-70%) by extrusion film blowing.
Abstract: Incorporation of essential oils in biodegradable polymers produces functional sustainable packaging materials that can extend the shelf-life of foods through enhanced antimicrobial capacity. Carvacrol was incorporated in poly(lactic acid) (PLA) and poly(butylene adipate terephthalate) (PBAT) blends at different polymer proportions (30–70%) by extrusion film blowing. Biodegradable films were characterized for morphology, thermal transition and mechanical and barrier properties. Stronger mechanical relaxation in PLA indicated plasticization effects of carvacrol, giving reduced relaxation temperature with enhanced exposure of PLA as a dispersed phase in PBAT matrices and improved compatibility. Polymer-polymer and polymer-carvacrol interactions involving C=O carbonyl bonds contributed to more homogeneous microstructures. Carvacrol plasticized films had dense matrices with increased crystalline fraction of PLA that reduced permeation of vapor and oxygen. Release rates of volatile carvacrol were enhanced in lower PLA matrices, while films showed delayed fungal growth and sporulation of Penicillium sp. and Rhizopus sp., with 2.0–2.3 times increased shelf-life of packaged bread and butter cake. Films containing plasticized carvacrol showed enhanced antifungal capacity, while PLA/PBAT blend ratios controlled the strength, permeability and release behavior of carvacrol.

57 citations


Journal ArticleDOI
TL;DR: In this article, Lactobacillus plantarum J26 was selected as the fermented strain in blueberry juice, and the basic indexes, nutritional functional properties, antioxidant capacity and enzyme inhibition were tested to judge the fermentation process influences to blueberry matrix.
Abstract: Lactic acid bacteria with various probiotic functions and excellent fermentation characteristics are widely used in food production, which not only enhance flavor, but also improve functional quality. In this research, Lactobacillus plantarum J26 was selected as the fermented strain in blueberry juice, and the basic indexes, nutritional functional properties, antioxidant capacity and enzyme inhibition were tested to judge the fermentation process influences to blueberry matrix. The results showed that the total amount of phenolic substances increased by 43.42% after fermentation. Four kinds of anthocyanins were found through High Performance Liquid Chromatography (HPLC) detection. Then the scavenging abilities of DPPH, superoxide anion radical and hydroxyl radical were estimated to determine the antioxidant activities of fermented blueberry juice. Moreover, the effect of oxidative damage was also analyzed in the model of Caco-2 cells. Finally, the inhibition of α-glucosidase and α-amylase were both detected in fermented blueberry juice. To sum up, these findings suggested that L. plantarum J26 could be used as fermented strain in the blueberry juice to improve the functional activities.

Journal ArticleDOI
TL;DR: In this paper, the authors used high pressure microfludizer to encapsulate eugenol (EUG), carvacrol (CAR) and cinnamaldehyde (CA) in oil-in-water nanoemulsion.
Abstract: Current study used high pressure microfludizer to encapsulate eugenol (EUG), carvacrol (CAR) and cinnamaldehyde (CA) in oil-in water nanoemulsion. The prime objective of this study was to explore the antifungal effect of these prepared nanoemulsion against Penicillium digitatum, and nanoemulsion coating effects on the shelf life of postharvest citrus fruits. The results showed that nanoemulsion has uniform particle size along with good centrifugal stability that has significant antifungal effect with MIC (0.125 mg/mL) and MFC (0.25 mg/mL) values. P. digitatum spore germination was significantly inhibited, and mycelial morphology was changed in a dose dependent manner and membrane permeability changed following nanoemulsion treatment. Furthermore, nanoemulsion coating could potentially reduce the citrus fruit decay rate, weight loss rate and respiratory rate. The soluble solids, vitamin C, and titratable acid contents degradation was delayed, while antioxidant enzyme activities were also significantly increased and maintained during postharvest storage. This study revealed that the nanoemulsion had better antifungal effect and great potential in prolonging the storage period of citrus fruits.

Journal ArticleDOI
TL;DR: In this article, the effects of low-frequency ultrasound induced conformational variation of duck liver globular proteins (DLGPs) on the binding behavior of n-alkenals based on multi-spectroscopic analysis combined with headspace solid phase microextraction technique were investigated.
Abstract: This work investigated the effects of low-frequency ultrasound (US) induced conformational variation of duck liver globular proteins (DLGPs) on the binding behavior of n-alkenals based on multi-spectroscopic analysis combined with headspace solid phase microextraction technique. Results suggested that US-treatments, with the frequency of 40 kHz and the power density of 26.7 W/L, induced obvious tertiary and quaternary structure changes of DLGPs, as revealed by fluorescence and ultraviolet–visible absorption spectroscopy, whereas the secondary and primary structures of DLGPs remained almost unaffected, suggesting the presence of molten-globule (MG) intermediates due to US-treatment. Meanwhile, the particles size and absolute values of ζ-potential exhibited significant increases as the functions of ultrasonic durations. According to multivariate results, the conformational variations, involving natural, MG and post-MG states, could be differentiated successfully. The US-induced conformational changes of DGLPs allowed it easier to interact with volatile n-alkenals, attributed to the enhanced hydrophobic interaction and covalent binding. Correspondingly, the headspace fractions of n-alkenals were greatly reduced after ultrasound pretreatments, with different degrees ranging from 5.61 to 59.39%, depending on chemical structures and processing conditions. This work suggests the great potential of specific conformational variations of DLGPs induced by ultrasonic pretreatments to modulate flavor features of protein-based products.

Journal ArticleDOI
TL;DR: In this paper, a new edible starch-based antibacterial composite film with thyme oil microemulsions (ME) or microcapsules(TMS) was prepared, and the slow-release characteristic, bacteriostatic property and the preservation effect on chilled meat of the films were evaluated.
Abstract: chilled meat is extremely susceptible to microbial contamination during processing and storage. Therefore, a new edible starch-based antibacterial composite film with thyme oil microemulsions(ME) or microcapsules(TMS) was prepared. The slow-release characteristic, bacteriostatic property and the preservation effect on chilled meat of the films were evaluated. The results showed that the cumulative release rates of composite films containing 5% microemulsion and 5% microcapsule were much less than the film containing 5% thyme oil. The antibacterial effect of film containing thyme oil microemulsion (ME-S) was stronger than that of film containing thyme oil microcapsule (TMS-S), but both of their antibacterial effect increased as the concentration increased. The overall fresh-keeping effect of composite films on chilled meat at 0–4 was blank

Journal ArticleDOI
TL;DR: In this paper, ultrasonic assisted extraction (UAE) was applied to enhance the extraction efficacy of protein from brewer's spent grain (BSG), and the effects of ultrasonic extraction conditions including power, time and duty cycle on the techno-functional properties of protein were also evaluated.
Abstract: Ultrasound assisted extraction (UAE) was applied to enhance the extraction efficacy of protein from brewer's spent grain (BSG). The effects of ultrasonic extraction conditions including power, time and duty cycle on the techno-functional properties of protein were also evaluated. The results demonstrated that in 110 mM sodium hydroxide solution, UAE working at 250 W for 20 min under duty cycle of 60% could significantly improve the protein yield to 86.16% compared with traditional extraction without ultrasound (45.71%). The structural analysis including CD, UV–Vis, SH content results and SDS-PAGE patterns clearly showed that BSG protein was modified under ultrasonication. The extracted BSG protein increased 5.83% of β-sheet content while decreased α-helix, β-turn and random coil contents by 4.76%, 0.33% and 0.74%, respectively. Besides, SDS-PAGE pattern of protein was slightly strengthened. The enhancement in SH content and UV–Vis spectra further indicated that exposure and unfolding of protein structure occurred and thus the functional properties of BSG protein were enhanced. Indeed, fat absorption capacity, emulsifying and foaming properties of BSG protein treated by UAE were all improved except for the water absorption capacity. Thus, UAE could be a promising method to separate protein from this valuable feedstock for further utilization in the food industry.

Journal ArticleDOI
TL;DR: In this article, the influence of acid type on the structure and properties of chitosan films was studied by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and differential scanning calorimetry (DSC).
Abstract: The properties of chitosan films can be modified by changing the solvent type, attributing to the different interaction patterns between chitosan and acids. However, little is known about how these interactions affect the structure and properties of chitosan films. In this work, the influence of acid type on the structure and properties of chitosan films was studied by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and differential scanning calorimetry (DSC). FTIR spectra showed that the ionic interactions and hydrogen bonding could occur between chitosan and acid ions. Structural analysis revealed that chitosan was partially crystalline in hydrochloric and acetic acid films, whereas it was amorphous in lactic and citric acid films. DSC result indicated that the glass transition temperature of chitosan was much lower in citric acid film with low water content than in all the other films, suggesting that the citrate ions interacted more strongly with chitosan. A melting transition appeared in hydrochloric and acetic acid films. In addition, the tensile strength of these films decreased with an increase in the volume of acid. These observations indicate that the choice of a proper solvent for chitosan may be desirable for certain special applications.

Journal ArticleDOI
TL;DR: In this paper, the authors evaluated the physical, mechanical, structural, morphological, antioxidant, and antimicrobial properties of chitosan-flaxseed mucilage (CH-FM) nanofibers enriched with Ziziphora clinopodioides essential oil (ZEO; 0, 0.25, and 0.75 ml/100
Abstract: The aims of the current study were to evaluate the physical, mechanical, structural, morphological, antioxidant, and antimicrobial properties of chitosan-flaxseed mucilage (CH-FM) nanofibers enriched with Ziziphora clinopodioides essential oil (ZEO; 0, 0.25, and 0.75 ml/100 ml) and sesame oil (SO; 0 and 0.75 ml/100 ml). Based on scanning electron microscopy images, the incorporation of ZEO 0.5 ml/100 ml, SO 0.75 ml/100 ml, and SO 0.75 ml/100 ml + ZEO 0.5 ml/100 ml caused an increase in the average diameters of the corresponding nanofibers. The atomic force microscopy images also showed smoother structures for nanofibers supplemented with ZEO and SO compared to the control group. The highest antimicrobial and antioxidant activities were found in CH-FM + ZEO 0.5 ml/100 ml + SO 0.75 ml/100 ml. The fabricated nanofibers had tensile strength, puncture force, puncture deformation, water vapor transmission rate, water vapor permeability, and swelling index ranging 3.52–5.55 MPa, 4.24–8.01 N, 1.15–3.45 mm, 25.01–47.49 g/m2 h, 7.98–14.08 × 10‾4 g mm/m2 h Pa, and 19.41–41.35%, respectively. Encapsulated ZEO and SO could also diffuse out slowly but durably from the nanofibers within 96 h. Our findings can give insights regarding prepared novel nanofibers containing antimicrobial/antioxidant compounds for food packaging applications.

Journal ArticleDOI
TL;DR: In this paper, the authors used the response surface methodology with composite central design to maximize ultrasound-assisted extraction of fat soluble pigments from mandarin epicarp for use as a natural colorant in two bakery products.
Abstract: Adding value to fruit by-products would satisfy global demand for natural additives and reduce impacts on the environment. Therefore, the objective of the present study was to optimize the process of ultrasound-assisted extraction of total carotenoids from mandarin epicarp for use as a natural colorant in two bakery products. The response surface methodology with composite central design were used to maximize ultrasound-assisted extraction of fat soluble pigments. Optimization of carotenoid extraction was achieved when the ultrasound process was carried out at a temperature of 60 °C for 60 min with a solid to liquid ratio of 0.0004 g/mL, where the maximum extraction of total carotenoids was 140.70 ± 2.66 mg β-carotene/100 g of dry sample. The carotenoid lipid extracts obtained from the tangerine epicarp could be a natural coloring additive with the potential to reduce the use of tartrazine in bakery products such as cakes and bread.

Journal ArticleDOI
TL;DR: In this paper, the potential of high pressure processing, high pressure homogenization, ultra-high-pressure homogenisation, high-pressure carbon dioxide/supercritical carbon dioxide, and their updated applications to better preserve the quality of fruit juices and beverages is reviewed.
Abstract: Clean-label foods have gained a lot of attention since it meets consumers’ interests in minimally processed food having a minimal number of ingredients and free from artificial additives. Increased interest in premium quality food products stimulated the integration of high-pressure technologies in food processing compared to conventional thermal processing. While commercial thermal pasteurization is effective in preserving beverages; high pressure-based processing technologies ensure a substantial decrease in microorganisms and spoilage enzymes as well as ensuring minimal impact on the nutrients content and sensory quality. Therefore, this article reviews the potential of high-pressure processing, high-pressure homogenization, ultrahigh-pressure homogenization, high-pressure carbon dioxide/supercritical carbon dioxide, and their updated applications to better preserve the quality of fruit juices and beverages. Pressure-based technologies can assist in reducing the number of ingredients by eliminating the need for certain additives for product stability and preservatives used for food safety and shelf-life extension. Available data highlight important limitations for clean-label food production, represented by the need to establish pressure optimization, microbiological and safe handling in the absence and/or in the presence of a low level of synthetic preservatives. More research is needed for reliable process validation with a focus on process characterization (temperature fields, thermal heterogeneity, and residence time distributions) and sterilization indicators, or mixtures thereof, to implement this promising technology.

Journal ArticleDOI
TL;DR: In this article, the authors evaluate the performance of the AlCl3 colorimetric assay for the determination of total flavonoid content (TFC) and provide conclusive evidence highlighting conceptual and methodological flaws.
Abstract: Flavonoids are important natural bioactive compounds. Quantitation of total flavonoid content (TFC) is widely performed using the aluminum chloride colorimetric assay against a flavonoid standard assuming equal responses from all flavonoids. The aim of this work was to critically evaluate the assay employing spike recovery in plant extracts and three authentic flavonoid standards (catechin, quercetin, and rutin). Due to the inherent variations in absorbance values at quantitation wavelengths between investigated flavonoids, the assay produced huge unacceptable differences in TFC. For trials involving AlCl3 alone in standard solutions, false-positive results were obtained (63–124%) when quercetin content was expressed as rutin equivalents. Conversely, false-negative results were found (26–42%) when rutin concentration was expressed as quercetin equivalents. Similarly, unacceptable spike recoveries were recorded (8–106%) when involving AlCl3 alone in standard solutions at all investigated wavelengths. For plant extracts, unacceptable differences (58–152%) in TFC were also obtained when either quercetin or rutin was used as a quantitation standard. When AlCl3 is used in conjunction with sodium nitrite, unacceptable high or low recoveries were noted depending on the quantitation standard used. The findings of this work provide conclusive evidence highlighting conceptual and methodological flaws in the AlCl3 colorimetric assay for the determination of TFC.

Journal ArticleDOI
TL;DR: Wang et al. as mentioned in this paper investigated variations of overall flavor characteristics in shiitake mushrooms (Lentinula edodes) affected by different drying techniques (hot air-drying (HD), vacuum freeze-dough (VFD), and VFD combined with HD) and concluded that VFD-HD preserved aroma compounds effectively.
Abstract: New insight was systematically elucidated on variations of overall flavor characteristics in shiitake mushrooms (Lentinula edodes) affected by different drying techniques (hot air-drying (HD), vacuum freeze-drying (VFD), and VFD combined with HD (VFD-HD)). The volatile fingerprints of shiitake mushrooms were successfully established by headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS), and taste profiles and concentrations of non-volatile substances in mushrooms were analyzed. Comparison of aroma fingerprints associated with three drying approaches demonstrated that HD caused considerable losses of volatile compounds except for volatile acids, while VFD and VFD-HD preserved aroma compounds effectively. By application of PLSR analysis, strong “seasoning-like” and “fruity” aromas of VFD-HD mushrooms were closely correlated with 2,6-dimethylpyrazine and esters respectively. Additionally, the umami intensity of VFD-HD mushrooms was similar to HD samples and significantly higher than VFD ones. Furthermore, the correlation between the electronic tongue and sensory attributes was explored. The results obtained from this study revealed that VFD-HD could combine the advantages of single HD and VFD, producing high flavor quality mushroom products.

Journal ArticleDOI
TL;DR: In this article, the volatile compounds in fresh watermelon juice (FW) and thermally treated watermelon juice (TW) were analyzed using HS-GC-IMS and GC-O-MS.
Abstract: Previously, the aroma compounds in watermelon juice were analyzed by either GC-MS or GC-O. These methods could not extract and analyze the volatile compounds comprehensively. Compared to the previous studies, for accurately identifying the aroma profile, the volatile compounds in fresh watermelon juice (FW) and thermally treated watermelon juice (TW) were analyzed using HS-GC-IMS and GC × GC-O-MS. Twenty-three compounds were detected by HS-GC-IMS, among them, allyl methyl sulfide, acetoin, and pentanal were identified for the first time in TW. Through GC × GC-O-MS analysis, 130 and 140 compounds were detected in FW and TW, respectively, and 36 and 38 of these compounds were smelled. In this study, 2,6-dimethyl-5-heptenal was identified for the first time in FW as an odor-contributing compound. These two kinds of juices could be differentiated by heat-mapping. The concentrations of (E)-2-decenal, decanal, 2-hexenal, 2-pentylfuran, and 6-methyl-5-hepten-2-one increased greatly by Volcano plot, and they contributed to the off-flavor in TW. For aroma analysis of watermelon juice, HS-GC-IMS can rapidly analyze the samples with low detection limits without pretreatment, while GC × GC-O-MS can precisely identify the compounds with sniffing. The results of this study suggest that HS-GC-IMS and GC × GC-O-MS can analyze the aroma profile more comprehensively and discriminate FW and TW more efficiently.

Journal ArticleDOI
TL;DR: In this article, the effect of ultrasonic intensity on the wheat starch-monoglyceride complex (WSG) and the influence of WSG on the quality of steamed bread were investigated.
Abstract: The effect of ultrasonic intensity on the wheat starch-monoglyceride complex (WSG) and the influence of WSG on the quality of steamed bread were investigated. With the increase of ultrasonic intensity, the complex index (CI) of the WSG first increased and then decreased. X-ray diffraction showed that with the addition of monoglycerides, the crystal type of starch changed from A-type to V-type. Fourier transform infrared spectroscopy showed that the absorption peak of the WSG was weaker than that of the control, and the characteristic peaks of the WSG complex appeared. Compared to native starch, the resistant starch (RS) content of WSG increased. When the ultrasonic intensity was 375 W, the CI value and RS content of WSG samples reached the maximum. WSG treated with 375 W of ultrasonic intensity was added to the steamed bread. The results showed that WSG addition decreased the specific volume and springiness of steamed bread, but dramatically increased its spread ratio, hardness, and chewiness. However, the excessive addition of WSG was not conducive to the quality of steamed bread. Flour blends with 5-10% WSG produced steamed bread with total scores comparable to the control flour. The results would provide new insights into starch under ultrasound treatment.

Journal ArticleDOI
TL;DR: In this paper, the physicochemical and functional characteristics of citric acid (CA)-treated whey protein isolate (WPI) by dynamic high pressure homogenization (DHPH) at different pressure levels (0, 25, 50, 75, and 100 MPa, 3 cycles) were investigated.
Abstract: This study investigated the physicochemical and functional characteristics of citric acid (CA)-treated whey protein isolate (WPI) by dynamic high-pressure homogenization (DHPH) at different pressure levels (0, 25, 50, 75, and 100 MPa, 3 cycles). The number of macromolecular polymers increased in CA-treated WPI with DHPH at 0–100 MPa by the analysis of molecular size distributions. DHPH can reduce the particle size of WPI and CA-treated WPI. Additionally, the content of free sulfhydryl groups and surface hydrophobicity of WPI and CA-treated WPI increased after DHPH treatment (p

Journal ArticleDOI
TL;DR: In this article, the authors developed composite (CG-TA) films by using chitosan (CS)/gelatin (GL)/tannic acid (TA), for fresh-cut apples preservation.
Abstract: The aim of this research is to develop composite (CG-TA) films by using chitosan (CS)/gelatin (GL)/tannic acid (TA), for fresh-cut apples preservation. TA was used as the crossing-linking agent to improve the mechanical and barrier properties, and as the active substance to improve the anti-ultraviolet and antioxidant abilities of the chitosan/gelatin (CG) film. With the incorporation of TA from 0 to 1 wt%, the tensile strength of the CG film was increased while the water vapor and oxygen permeability of the film were decreased. The CG-TA films containing more than 0.5 wt% of TA could effectively block most of UV light. The DPPH radical scavenging assay significant increased to 89.3% when the concentration of TA reached 2 wt%. Finally, CG and CG-TA films, as an active packaging material, were used to preserve the cold-stored fresh-cut apples. Compared with CG film, the CG-TA films obtained better performance on decreasing weight loss, delaying browning degree, inhibiting the lipid oxidase activity and decreasing the malondialdehyde content during 10 d of storage under 4 °C. Therefore, CG-TA films were expected to be a new active packaging material for preserving fresh-cut apples.

Journal ArticleDOI
Jie Liu1, Liru Zhang1, Chang Liu1, Xuejing Zheng1, Keyong Tang1 
TL;DR: In this article, a series of pullulan dialdehyde (PDA) with different molecular weights and aldehyde contents were successfully synthesized by periodate oxidation, and subsequently used for crosslinking gelatin edible films.
Abstract: Tuning structure of gelatin edible films by crosslinking with oxidized polysaccharides is a highly interesting approach, as thereby the random coil structure of gelatin changes towards a covalent network and thus the properties can be tailored. With this aim, a series of pullulan dialdehyde (PDA) with different molecular weights and aldehyde contents were successfully synthesized by periodate oxidation of pullulan, and subsequently being used for crosslinking gelatin edible films. The inclusion of PDA in gelatin films induced chemical crosslinking between the protein chains and consequently improved their water vapor barrier property and thermal properties. The water solubility of gelatin films decreased from 42.3 ± 2.1% to 18.7 ± 0.5% after PDA crosslinking, while the tensile strength of the crosslinked gelatin films was about 2.7 times that of neat gelatin film. Furthermore, PDA crosslinking provoked a significant browning coloration of the gelatin films, accompanied by a significant improvement in UV light barrier property. The results also indicated that the molecular weight of PDA might play an important role in affecting the network structure and properties of gelatin films. Collectively, PDA crosslinking can be considered to be a potential alternative for tuning structure and properties of gelatin edible films.

Journal ArticleDOI
TL;DR: In this article, a high-fiber high-protein composite flour matrix was selected as the food vehicle and four encapsulation techniques (Spray drying, freeze drying, spray-freeze drying, and refractance window drying) were used for the production of probiotic encapsulates in fructooligosaccharide: whey protein: maltodextrin matrix.
Abstract: The increasing demand for functional foods is associated with the need to deliver probiotics through novel food matrices. In this study, a high-fiber high-protein composite flour matrix was selected as the food vehicle. To improve their stability, four encapsulation techniques (spray drying, freeze drying, spray-freeze drying, and refractance window drying) were used for the production of probiotic encapsulates in fructooligosaccharide: whey protein: maltodextrin matrix. Considering the need to develop customized/personalized products, the material supply was 3D printed using an in-house developed extrusion-based food 3D printer CARK (controlled additive-manufacturing robotic kit). The effect of four post-processing methods (freeze drying, refractance window drying, hot air drying, and microwave drying) was explored and the overall effect on probiotic stability during storage under two different conditions (4 °C and room temperature) was evaluated. No significant loss of probiotic viability was observed during the 3D printing process. Freeze drying method of post-processing achieved >90% survival rate for freeze dried and spray-freeze dried synbiotics incorporated products. Among the various treatments, spray-freeze-dried synbiotics incorporation followed by freeze drying post-processed 3D printed construct showed the best survival rate (79%) and viability (6.43 ± 0.17 log10 CFU/ml) under static in vitro digestion conditions. With around 96–98% survival rate with retained viability of 7.98 ± 0.48 log10 CFU/ml during the storage period of 35 days, the approach shows promising prospects for the delivery of probiotics in prebiotic matrices of customized shapes.

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TL;DR: In this paper, the UHPLC-Orbitrap MS4 analysis showed the presence of 75 phenolic compounds (57 non-anthocyanins and 18 anthocyanin), among which considerable content of ethyl gallate was observed and malvidin-3-O-hexoside-(8,8)-methylmethyne-(epi)catechin was identified.
Abstract: Phenolic compounds and biopotential (antioxidant, cellular antioxidant and cytotoxic activity) of grape pomace (GP) skin, seed, stem and whole GP originating from indigenous red grape variety Prokupac were evaluated. The UHPLC-Orbitrap MS4 analysis showed the presence of 75 phenolic compounds (57 non-anthocyanins and 18 anthocyanins), among which considerable content of ethyl gallate was observed and malvidin-3-O-hexoside-(8,8)-methylmethyne-(epi)catechin was identified. The stem had significant content of stilbenoids. The GP seed and the whole GP showed the highest antioxidant activity estimated by ABTS•+ DPPH• and H2O2 scavenging assays that were strongly correlated with the presence of flavan-3-ols, phenolic acids and ethyl gallate. The GP skin exerted cellular antioxidant activity on adenocarcinoma cells (EC50 = 56.4 mg TPCs/mL) which was strongly correlated with the presence of flavonols and anthocyanins. These by-products of Prokupac red grape variety are a notable source of phenolic compounds with good antioxidant activity that can be extensively used in food and pharmaceutical industry.

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TL;DR: In this paper, a biopolymer-based antimicrobial fibrous membranes constituted by polylactic acid (PLA) and ultrasonically dispersed ZnO nanoparticles (NPs) were developed by electrospinning.
Abstract: In this study, biopolymer-based antimicrobial fibrous membranes constituted by polylactic acid (PLA) and ultrasonically dispersed ZnO nanoparticles (NPs) were developed by electrospinning. The morphology, mechanical properties, thermodynamics and antimicrobial properties of membranes with different ZnO NPs content were comprehensively studied. The results showed that the best performance was achieved when the content of ZnO content was 0.5 wt% (PLA/ZnO-0.5%). Specifically, the tensile strength and elongation at break of the composite membrane were 6.85 ± 0.19 MPa and 74.90 ± 0.59%, respectively, and the inhibition zones of Escherichia coli and Staphylococcus aureus were 15.02 ± 0.18 mm and 14.74 ± 0.06 mm, respectively. In addition, an appropriate ultrasonication time of 45 min improved the thermal, ultraviolet (UV) barrier, and antibacterial properties of the composite membrane. At the 45 min ultrasonication time, the inhibition zone of PLA/ZnO-0.5% against Escherichia coli and Staphylococcus aureus was 18.11 ± 0.15 mm and 15.80 ± 0.11 mm, respectively. Therefore, PLA/ZnO-0.5% can be applied in food packaging to provide an antibacterial effect and UV light barrier.

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TL;DR: In this paper, the improvement in antibacterial properties of grapefruit peel essential oil after the nano-emulsification process was investigated, and the essential oil composition was characterized using GC-MS, with d -Limonene being the main identified compound (82.86%).
Abstract: In the study, improvement in antibacterial properties of grapefruit peel essential oil after the nanoemulsification process was investigated. The essential oil composition was characterized using GC-MS, with d -Limonene being the main identified compound (82.86%). The antibacterial properties against common food-borne pathogens (Staphylococcus aureus, Enterococcus faecalis, Klebsiella pneumoniaand Salmonella Paratyphi A) as well as 6 fish-spoilage bacteria isolated from 4 spoiled fish species: mackerel, sardine, anchovy and rainbow trout, have been evaluated using paper disc diffusion, MIC and MBC methods. The grapefruit peel essential oil showed bacteriostatic properties against the majority of tested bacterial strains, however, only the growth of Salmonella parathypi A, Vibrio vulnificus and Seratialique faciens was inhibited by the essential oil in the concentration up to 25 mg/mL. Incorporation of essential oil into the nanoemulsion system resulted in increased bacteriostatic potency when the oil concentration in the nanoemulsion were considered, however, no bactericidal effect was observed, which was probably due to too low concentration of essential oil in the nanoemulsion system. The improvement in the nanoemulsion preparation method and formulation should be investigated to further improve its antibacterial properties.