Tannase improves gallic acid bioaccessibility and maintains the quality of mango juice

The effect of tannase on gallic acid (GA) bioaccessibility and auto-oxidative browning of mango juice was investigated. After 2 h of simulated gastric digestion, the concentration of bioaccessible GA increased (P < 0.05) 94.3 ± 7.0% in juice treated with 0.5 U mL⁻¹ tannase while juice not treated with tannase had only a 6.3 ± 3.4% increase in GA. During 2–10 h of simulated intestinal digestion, tannase treated juice continued to have a higher concentration (P < 0.05) of bioaccessible GA in comparison to juice that was not treated with tannase. The use of 167 U 100 mL⁻¹ tannase while processing mango juice did not result in any differences (P < 0.05) in browning measured at 420 nm, yet there was significantly higher (P < 0.05) GA in mango juice post-storage. Processing mango juice with tannase can help improve the bioaccessibility of mango polyphenols without hindering the quality of juice during storage.     

Use of nanoliposome loaded with chitosan-epigallocatechin gallate conjugate for shelf-life extension of refrigerated Asian sea bass (Lates calcarifer) slices

Treatments of chitosan-epigallocatechin gallate (CE) conjugate nanoliposome (CELP) and unencapsulated CE conjugate (UNCE) at different concentrations (0.025  and 0.05 g 100 g⁻¹) on quality and shelf-life of Asian sea bass slices (ASB-S) kept at 4 °C were studied. Total viable count of ASB-S treated with 0.05 g 100 g⁻¹ CELP (SB-CELP-0.05) was less than permissible limit (6 log CFUg⁻¹ sample) within 15 days. Moreover, SB-CELP-0.05 sample had the lowest pathogenic and spoilage bacterial count than remaining samples during the storage (P < 0.05). Lower thiobarbituric acid reactive substances and peroxide values were obtained for SB-CELP-0.05 sample than those treated with 0.05 g 100 g⁻¹ UNCE (SB-UNCE-0.05) at the end of storage (P < 0.05). The result was also advocated by higher polyunsaturated fatty acid content of SB-CELP-0.05 than SB-UNCE-0.05 (P < 0.05). Therefore, CELP efficiently extended ASB-S shelf-life with high consumer acceptability at 4 °C for minimum 12 days, whereas control had the shelf-life less than 6 days.     

Evaluation of structural changes in raw and heated meat batters prepared with different lipids using Raman spectroscopy

Structural changes, textural properties, water- and fat-binding properties and their relationships in meat batters prepared with different lipids and with heating were studied by Raman spectroscopy. Results revealed that the meat batters prepared with soybean oil (SO) showed the lowest fluid losses, greatest (P < 0.05) hardness, springiness, cohesiveness, chewiness, resilience values compared with batters prepared with pork fat (PF) or butter (DB). There was a significant decrease (P < 0.05) in α-helix content accompanied by a significant increase (P < 0.05) in β-sheet structure after heating in PF and SO samples, but no significant (P > 0.05) difference was found in DB batters. A positive significant (P < 0.05) correlation between β-sheet structure and textural properties was found in heated samples. Further, there was a significant positive (P < 0.05) correlation between α-helical structure and total expressible fluid and a significant negative (P < 0.05) correlation between β-sheet structure and total expressible fluid. Results suggest that different lipid additions and thermal treatments induced different changes in meat proteins structural, expressible fluid, and textural properties of meat batters.     

Utilising grape juice processing by-products as bulking and colouring agent in white chocolate

In this study, grape pomace (mixture of grape seeds and skins) powder (GPP), obtained from grape processing, was used at different concentrations [10.0 (GPP10), 20.0 (GPP10) and 30.0 (GPP10) g/100 g] in white chocolate formulation for the partial replacement of sucrose. The results indicated that GPP addition at a higher concentration (>10.0 g/100 g) significantly affected the particle size, moisture content, texture and flow behaviour of white chocolate samples (P < 0.05). However, using GPP at a concentration of 10.0 g/100 g had advantages for physicochemical and flow properties. As expected, under simulated in vitro digestion conditions, the bioaccessibility of total phenolic compounds in saliva, gastric juice and intestinal juice for GPP10 samples was significantly higher than the control (P < 0.05). In conclusion, results of the study showed that it was possible to partially replace the sucrose with GPP at a concentration of 10.0 g/100 g in white chocolate formulations.     

Effect of encapsulated Lactobacillus plantarum as probiotic on dry-sausages during chilled storage

The impact of free and encapsulated Lactobacillus plantarum addition on the physicochemical and microbiological properties during chilled storage (60 days) of dry-fermented sausages have been studied. Control (C) treatment was performed without probiotic incorporation, and the reformulation was comprised of L. plantarum as free cells (F) in alginate spheres (EA), in water-in-oil simple emulsion (ESM) and in water-in-oil-in-water double emulsion (EDM). After 60 days of storage, lower (P < 0.05) lipid oxidation was observed in F and EA (0.602–0.625 mg MDA kg⁻¹) while it was higher (P < 0.05) in EDM (1.949 mg MDA kg⁻¹). Treatments C and ESM presented intermediate TBARS levels compared to other treatments at the end of storage. All dry-fermented sausages presented high levels of lactic acid bacteria during the whole chilled storage (8.06–9.29 log CFU g⁻¹ at day 0 and 8.02–9.35 log CFU g⁻¹); however, EA treatment presented the highest L. plantarum viability even at 60 days of storage (8.34 log CFU g⁻¹). Therefore, the strategy of L. plantarum inoculation in alginate spheres seems to be the best strategy for the delivery of probiotics during chilled storage of dry-fermented sausages.     

Evaluation of rheological properties,microstructure and water mobility in buns dough enriched in aleurone flour modified by enzyme combinations

This study aimed to explore the differences between single enzyme and combined enzymes in improving buns dough quality characterised by changes in rheological properties, microstructure and water mobility. The results indicated that xylanase (60 μg g⁻¹)–glucose oxidase (GOX) (40 μg g⁻¹) and xylanase (60 μg g⁻¹)–glucose oxidase (40 μg g⁻¹)–cellulase (30 μg g⁻¹)-modified dough can improve the negative effects of the single enzyme on the dough in terms of extensibility, tenacity and stability, leading to the formation of a softer gluten matrix. This may be due to xylanase (60 μg g⁻¹)–GOX (40 μg g⁻¹) and xylanase (60 μg g⁻¹)–GOX (40 μg g⁻¹)–cellulase (30 μg g⁻¹)-modified dough reduced the free sulfhydryl and significantly increased water-extractable arabinoxylan content (P < 0.05) and enhanced more less-tightly bound water availability. The microstructure observation showed that xylanase (60 μg g⁻¹)–GOX (40 μg g⁻¹) and xylanase (60 μg g⁻¹)–GOX (40 μg g⁻¹)–cellulase (30 μg g⁻¹) modified dough exhibited a more compact and continuous gluten matrix.     

Evolution of lipid damage and volatile amine content in Patagonian squid (Doryteuthis gahi) by-products during frozen storage

By-products (viscera, tails, skin, etc.) resulting from Patagonian squid (Doryteuthis gahi) commercialisation were pooled together and stored at −10 and –18 °C for 12 months. During this storage time, 81.1–83.7 and 1.7–2.4 (g 100 g⁻¹) ranges were detected for moisture and lipid values, respectively. An increased storage time and temperature led to free fatty acid formation and phospholipid content decrease (P < 0.05). Meantime, peroxide levels were low and included in 2.1–3.6 meq. active oxygen kg⁻¹ lipids range. Contrary, substantial formation (P < 0.05) of thiobarbituric acid reactive substances and fluorescent compounds was proved, values being higher by increasing the time and temperature of storage of squid by-products. Related to amine formation, trimethylamine values increased notably (P < 0.05) with storage, higher values being obtained by increasing the storage time and temperature. For total volatile amines, increased levels with storage time were detected in samples stored at −10 °C; contrary, by-products stored at the lowest temperature tested did not provide differences (P > 0.05), resulting from the storage time. This study shows the need of appropriate storage conditions to offer the current by-products as a source of valuable marine constituents. Present results meet the present global interests in the search for new and undervalued marine substrates to be employed commercially.     

Impact of lecithin incorporation on gel properties of bigeye snapper (Priacanthus tayenus) surimi

Gelling characteristics of bigeye snapper (Priacanthus tayenus) surimi functionalised by lecithin at different concentrations were investigated. Lecithin at ≤1 g 100 g⁻¹ had no impact on breaking force and deformation (P > 0.05). Expressible drip tended to decrease with increasing lecithin level up to 1 g 100 g⁻¹. Lecithin at 1–3 g 100 g⁻¹ improved the whiteness (P < 0.05). Jointed clusters were formed in the gel microstructure with 1 g 100 g⁻¹ lecithin. Gel without and with 1 g 100 g⁻¹ lecithin had the same texture profile and likeness scores (texture, odour and flavour) (P > 0.05). Peroxide value, TBARS content and rancid odour score of gels were changed considerably during refrigerated storage (4 °C/polyethylene bag) for 15 days but lower values of all indices were noticeable in gel with lecithin. Therefore, lecithin at 1 g 100 g⁻¹ was the optimum concentration for stabilising the texture, improving the water holding capacity, whitening the colour and retarding the lipid oxidation of bigeye snapper surimi gel.     

Alginate-based coatings charged with hydroxyapatite and quercetin for fresh-cut papaya shelf life

In this study, the effect of alginate-based coatings charged with quercetin glycoside compounds and hydroxyapatite/quercetin glycoside compounds (HA/QUE) on the microbiological quality, and on bioactive compounds of fresh-cut papaya, was evaluated for 14 days at 6 °C. Alginate coatings with hydroxyapatite/quercetin showed a high capability to slow down the growth of all microbiological parameters investigated. At the end of cold storage, the total bacteria count in papaya samples covered with HA/QUE alginate coating was 4.8 log CFU g⁻¹ which is significantly lower (P < 0.05) than 8.3 log CFU g⁻¹ for uncoated samples. Total carotenoids’ percentage decrease, at the end of storage, was about 20% in papaya with active coatings, with respect to the losses of 39 and 35%, registered in uncoated and alginate-coated samples respectively. Vitamin C content and the antioxidant activity measured in papaya coated with HA/QUE alginate showed significantly higher values (P < 0.05) for each storage day than those detected for control- and alginate-coated samples. Based on the sensory evaluation, active-coated fresh-cut papaya reached, at the end of the storage period, suitable values for commercial purposes.     

Comparative analysis of charcoal grilling,infrared grilling and superheated steam roasting on the colour,textural quality and heterocyclic aromatic amines of lamb patties

The colour, textural profile and heterocyclic aromatic amines content of lamb patties cooked by charcoal grilling, infrared grilling and superheated steam roasting were investigated. The results of colour showed that lightness and yellowness values were highest in the superheated steam and lowest in charcoal grilled patties. The texture characteristics observed in the superheated steam, and infrared patties were much better. Water loss was highest in charcoal grilled meat. Charcoal grilling produced a significantly (P < 0.05) much higher amount of total HAAs, ranging from 171.26 ng g⁻¹ to 555.29 ng g⁻¹ (polar) and from 200.77 ng g⁻¹ to 426.07 ng g⁻¹ (non-polar) HAAs, than infrared (39.21 ng g⁻¹ −181.37 ng g⁻¹⁾ and (52.84 ng g⁻¹ −148.59 ng g⁻¹) and superheated steam roasting (from 8.67 ng g⁻¹ to 30.66 ng g⁻¹ and from 23.61 ng g⁻¹ to 89.66 ng g⁻¹⁾ for both types of HAAs in lamb patties. Colour, texture and HAAs were significantly influenced by time and by the temperature used for each cooking method.     

Effects of carboxymethylation,hydroxypropylation and dual-enzyme hydrolysis combination with heating on in vitro hypoglycaemic properties of coconut cake dietary fibres

Effects of carboxymethylation, hydroxypropylation and dual-enzyme hydrolysis combined with heating on in vitro hypoglycaemic properties of coconut cake dietary fibre (CCDF) were studied. Results showed that all the three modification methods could effectively improve (P < 0.05) the glucose-adsorption ability (GAA), glucose dialysis retardation index (GDRI), α-glucosidase and α-amylase inhibition activity of CCDF. The highest GAA (4.45–4.93 mm  g⁻¹), GDRI (85.09–86.94% mm  g⁻¹) and α-glucosidase inhibition activity (16.39–19.37%) were found on CCDFs modified by hydroxypropylation and carboxymethylation, attributed to the increased soluble dietary fibre content, viscosity and water retention and swelling capacity. Moreover, CCDF treated by enzymatic hydrolysis combined with heating demonstrated the highest α-amylase inhibition activity (53.95%), attributed to the high specific surface area, more porous surface structure and formation of fibre–amylase complex proved by fluorescence spectroscopy. These results suggest that the modified CCDFs could be used as low-calorie functional ingredients in food or other industries.     

Effect of commercial adjunct cultures on proteolysis in low-fat Kefalograviera-type cheese

The effect of two commercially available adjunct cultures, LBC 80 (Lactobacillus casei subsp. rhamnosus) and CR-213 (containing Lactococcus lactis subsp. cremoris and Lc. lactis subsp. lactis) on the proteolysis in low-fat hard ewes’ milk cheese of Kefalograviera-type was investigated. Two controls, a full-fat cheese (306 g kg⁻¹ fat, 378 g kg⁻¹ moisture) and a low-fat cheese (97 g kg⁻¹ fat, 486 g kg⁻¹ moisture, made using a modified procedure), were also prepared. The effect of adjunct culture on proteolysis, as examined by polyacrylamide gel electrophoresis of cheese and water soluble cheese extracts, was marginal. The reverse-phase HPLC peptide profiles of the water soluble extracts from low-fat cheeses were similar although some quantitative differences were observed between low-fat control cheese and experimental cheeses. The fat content as reflected by the differences in peptide profiles affected the pattern of proteolysis. Proteolysis, as measured by the percentage of total nitrogen soluble in water or in 120 g L⁻¹ trichloroacetic acid, was significantly (P<0.05) affected by the addition of adjunct cultures. Furthermore, the adjunct cultures enhanced the production of low molecular mass nitrogenous compounds; the levels of total nitrogen, soluble in 50 g L⁻¹ phosphotungstic acid, and of free amino acids were significantly (P<0.05) higher in the low-fat experimental cheeses than in the low-fat control cheese.     

Inactivation of pectin Methylesterase and Lactobacillus Plantarum by ohmic heating in pomelo juice

The use of ohmic heating (OH) to inactivate damaging elements in pomelo juice was evaluated. The work investigated the effect of frequencies (50–20 000 Hz) on pectin methylesterase (PME) and Lactobacillus plantarum (L. plantarum) in pomelo juice at 30 V cm⁻¹ of electric field strength. The results show that frequency does not affect PME inactivation (P > 0.05) but affects bacterial reduction and has the most efficiency at 60 Hz, followed by 50 Hz, and in the frequency range at or higher than 500 Hz (P < 0.05). Additionally, the inactivation kinetics of PME and L. plantarum and the impact of nonthermal factors were given. The nonthermal element has contributed to the inactivation enhancement of L. plantarum and PME to reduce the necessary treatment temperature and time. The major spoilage bacteria and enzyme destruction in pomelo juice occurred faster under OH than under conventional heating (CH) suggesting that OH can be effectively used to pasteurise pomelo juice.     

Polyphenolic composition,antioxidant and antiproliferative effects of wild and cultivated blackberries (Rubus fruticosus L.) pomace

The content of total polyphenolics, antioxidative capacity and antiproliferative activity were tested in wild and cultivated blackberry pomace. Wild blackberry pomace extract Tw2 showed the highest following contents: total polyphenolics (50.16 mg GAE g⁻¹ dw), flavonoids (7.73 mg Qc g⁻¹ dw), flavonols (6.63 mg Qc g⁻¹ dw) and total monomeric anthocyanins (13.40 mg Cy g⁻¹). Tw2 extract significantly inhibited free radicals: IC₅₀^DPPH = 127.76 μg mL⁻¹, IC₅₀^ABTS = 26.53 μg mL⁻¹ and IC₅₀ ^{˙ OH} = 168.62 μg mL⁻¹, and the growth of breast adenocarcinoma IC₅₀^MCF7 = 306.68 μg mL⁻¹ and cervix epitheloid carcinoma cell lines IC₅₀^HeLa = 315.49 μg mL⁻¹. Wild blackberry varieties had higher extraction yields, higher total polyphenolic contents and possessed stronger biological effects compared to cultivated blackberries (P < 0.05). All blackberry extracts showed high biological potential that could be attributed to high total polyphenols and flavonoids content and could be utilised as value-added functional food.     

Development and quality characteristics of functional Kulfi fortified with microencapsulated betalains

Fruit and vegetable waste valorisation has opened opportunities for the utilisation of food waste for extraction and development of valuable functional foods. Therefore, the study was designed to develop a functional Kulfi fortified with encapsulated betalains extracted from red beetroot (Beta vulgaris L.) pomace. Moreover, fortified functional Kulfi samples were studied for physico-chemical, antioxidant, microbiological and sensory analyses. Fortified functional Kulfi reported the higher antioxidant activity (64.88% and 75.27%) with reduced melting rate (1.84 mL min⁻¹ and 2.08 mL min⁻¹) and microbial profile (3.77 log CFU g⁻¹ and 3.14 log CFU g⁻¹) compared with control. Sensory analysis showed a no significant (P > 0.05) impact on the overall acceptability of functional Kulfi (7.25) compared with the commercial Kulfi (7.20), which was further confirmed by a bi-plot of principal component analysis. Overall, the encapsulated betalains improved the quality characteristics of functional Kulfi and could be used for the development of frozen dairy products.     

Impact of Harvesting and Processing Conditions on Green Leaf Volatile Development and Phenolics in Concord Grape Juice

ABSTRACT: The disruption of plant cell walls during fruit juice processing results in the enzymatic formation of herbaceous-smelling green leaf volatiles (GLVs). Our objective was to assess the impact of thermal processing conditions on resulting levels of GLVs (hexanal, trans-2-hexenal, hexanol, cis-3-hexenol, and trans-2-hexenol), total phenols, monomeric anthocyanins, and percent polymeric color in Concord grape juice. The effects of fruit maturity and stage of juice processing on juice GLV content was also assessed. Of the GLVs studied, only trans-2-hexenal routinely exceeded its published sensory threshold in finished juice. We observed an inverse linear correlation between berry maturity (total soluble solids) and trans-2-hexenal levels in finished juice (P < 0.05, R ²= 0.91). Trans-2-hexenal was at a maximum immediately following crushing (569 μg/kg, >30-fold over detection threshold [DT]), decreased to 100 μg/kg following depectinization, pressing, and pasteurization, and to 32 μg/kg following cold-stabilization. The loss of trans-2-hexenal could be explained primarily by its reduction to trans-2-hexenol, which increased from 53 μg/kg after crushing to 500 μg/kg after cold-stabilization. High temperature pretreatment of must immediately following crushing (“hot break”) resulted in 5- to 6-fold higher concentrations of trans-2-hexenal in the final bottled juice as compared to conventional hot press. Contrary to expectations, no significant increase in phenolics and anthocyanins were observed in hot break conditions. These results indicate that hot break procedures may thermally inactivate enzymes responsible for transforming trans-2-hexenal under normal processing conditions and potentially alter the flavor qualities of the finished Concord juice. Different equivalent pasteurization regimes (82 to 93 °C) prior to bottling had no significant effect on GLV content of the finished Concord juices (P > 0.05). Practical Application: Introducing new processing techniques to fruit juice production can potentially result in undesirable changes to organoleptic properties. We have observed significantly higher levels of trans-2-hexenal, a potent herbaceous off-flavor, in Concord grape juice prepared with an initial high temperature heat treatment (“hot break”). Concord juice producers should be cautious in using hot break processing, especially with immature fruit, as it may result in persistence of green aromas in juice.     

Effect of salt content on gelation of normal and wooden breast myopathy chicken pectoralis major meat batters

This study investigated the effects of salt content (0–4%) on water holding capacity (WHC), textural characteristics, rheological properties, and microstructure of cooked normal (NOR) and wooden breast (WB) chicken meat batters. Results indicated with 0–2% salt addition, the WB batters had significantly lower WHC and storage modulus (G’) compared with the NORs (P < 0.05). However, these differences were eliminated when salt contents were increased to 3% or 4%. In addition, the NORs formed more regular and pored networks than the WBs (0–2%). Salt level significantly affected the textural properties of both batter types (P < 0.05). The hardness of the WB batters was lower than NORs at all NaCl levels (P < 0.05). Overall, compared with NORs, the WB batters showed inferior gelation properties at salt contents of 0–2%, while increasing salt content to 3–4% can improve the WHC and microstructure of gels.     

Fermented coconut jelly as a probiotic vehicle,physicochemical and microbiology characterisation during an in vitro digestion

There is little information on the survival of probiotics in plant-based foods after simulated gastric and intestinal conditions, likewise the microstructure arrangement in the no-dairy fermented food. This work aimed to study if the agar–agar in a fermented coconut jelly confers protection to probiotics, phenolic and antioxidant compounds during in vitro digestion. Samples containing higher agar–agar amounts tend to retain (P < 0.05) antioxidant and phenolic compounds in their network better, even after the in vitro digestion. Also, a compact and homogeneous microstructure was observed by the Confocal Laser Scanning Microscopy. The texture profile analysis shows that 1% of agar samples presented the maximum hardness (P < 0.05) due to more bonding points and intermolecular interactions. Finally, the survival of probiotics remained above the recommended values (10⁶–10⁷ CFU g⁻¹) after the in vitro digestion of a product with probiotic potential.     

An improved analytical method for determination of trans-resveratrol and related stilbenes in grape skin by QuEChERS coupled with HPLC-PDA-MS

Grape is a popular fruit crop that generates about one-fourth of total weight as pomace during winemaking and commercial juice production. However, a significant amount of resveratrol and related stilbenes is present in grape skin, and their effective isolation enables the production of functional foods. Herein, an improved analytical method for the determination of trans-resveratrol and related stilbenes in grape skin waste by QuEChERS method coupled with a high-performance liquid chromatograph-photodiode array detector-mass spectrometer was developed. By employing a Gemini C18 column and a mobile phase of acetic acid in water (pH 3.6) and acetonitrile, a total of five resveratrol and related stilbenes could be separated within 15 min with a flow rate of 0.8 mL min⁻¹ and detection wavelength at 306 nm. The optimised QuEChERS conditions were 10 mL of acetonitrile, 1 mL of grape skin extract and 900 mg of magnesium sulphate plus 25 mg of primary secondary amine. Principal component analysis by two principal components (74.18%, 25.82%) could well describe the trans-resveratrol recovery at different QuEChERS conditions. A mean recovery, as well as coefficient of variation (CV, %) of repeatability and intermediate precision, ranged from 96.6% to 104.4%, 1.96% to 3.10% and 1.68% to 4.27%, respectively, conforming to the regulation set by Taiwan Food and Drug Administration. Quantitation revealed cis-piceid to be present in largest amount (2.616 μg mL⁻¹), followed by trans-piceid (1.027 μg mL⁻¹), trans-resveratrol (0.967 μg mL⁻¹), ε-viniferin (0.660 μg mL⁻¹) and cis-resveratrol (0.183 μg mL⁻¹) in grape skin extract, with their corresponding contents in dried grape skin being 4.185, 1.643, 1.539, 1.056 and 0.293 μg g⁻¹, respectively.     

Rapid reversed-phase high performance liquid chromatographic method for the quantification of L-Dopa (L-3,4-dihydroxyphenylalanine), non-methylated and methylated tetrahydroisoquinoline compounds from Mucuna beans

A high-performance liquid chromatographic (HPLC) assay for the extraction and quantitative determination of L-Dopa, L-3-carboxy-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline and 1-methyl-3-carboxy-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline in Mucuna pruriens var. utilis seeds has been developed. All the three compounds, L-Dopa, CDTHIQ and MCDTHIQ in the white variety of whole (4.96 g 100 g⁻¹, 130.3 and 116.8 mg 100 g⁻¹) and dehulled (5.21 g 100 g⁻¹, 138.3 and 125.9 mg 100 g⁻¹) seeds have been found to be significantly (P<0.05) higher than the black variety, respectively. The method makes use of a reversed-phase system with a C₁₈-bonded column and yields quantitative recovery of all the three compounds, L-Dopa (101.8%), CDTHIQ (98.2%) and MCDTHIQ (94.5%). This procedure is superior to other analytical techniques currently available because of its simplicity with regard to sample preparation, the sensitivity and rapidity of the method.