The impact of chitosan film or chitosan/chitosan–epigallocatechin gallate conjugate composite film on the quality changes of Asian sea bass (Lates calcarifer) slices stored in air or under vacuum packaging

Quality and shelf-life of Asian sea bass slices (ASBS) wrapped with chitosan (CS)/CS–epigallocatechin gallate (CE) conjugate composite or CS films and packaged in air or under vacuum during storage at 4 °C were studied. Total viable count was less than permissible limit (6 log·CFU g⁻¹ sample) for ASBS wrapped with CS/CE conjugate composite film under vacuum (ASBS-COMP-VP) after 18 days. Moreover, lower microbial proliferation and volatile base contents were attained in ASBS-COMP-VP sample than other samples during the storage (P < 0.05). At the end of storage, ASBS-COMP-VP sample had lower lipid oxidation than those wrapped with CS film (P < 0.05). Polyunsaturated fatty acid content of ASBS-COMP-VP was retained at higher content at day 18. Therefore, ASBS-COMP-VP had the enhanced shelf-life with high acceptability up to 18 days at 4 °C, while ASBS wrapped with CS film and packaged in air or under vacuum had the shelf-life of 9 and 12 days, respectively.     

Extrusion improved the physical and chemical properties of dietary fibre from bamboo shoot by-products

Bamboo shoot by-products are regarded as waste and environmental pollutant. This study aimed to improve the functional properties of dietary fibre from bamboo shoot by-products. After CO₂ extrusion, the particle size of CO₂-extruded bamboo fibre was 17.6% lower than that of the control, and its specific surface area was 2.85 times that of the control. The soluble dietary fibre content was significantly increased from 5.64 g/100 g to 11.05 g/100 g (P < 0.05), and the capacities for water holding, swelling and oil holding were remarkably improved. The cholesterol adsorption of CO₂-extruded bamboo fibre was increased from 96.54 μg g⁻¹ to 174.65 μg g⁻¹ (pH 7.0), and its nitrite ion adsorption capacity was increased from 503.33 μg g⁻¹ to 657.27 μg g⁻¹ (pH 2.0). In summary, the structural changes of bamboo fibre such as internal porosity, surface roughening and low crystallinity indicated that its functional properties were improved after CO₂ extrusion.     

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.     

Fatty acids,volatile compounds and microbial quality preservation with an oregano nanoemulsion to extend the shelf life of hake (Merluccius hubbsi) burgers

Hake (Merluccius hubbsi) is the most important fish of Argentinean industry. The preservative effects of an oregano essential oil (EO) nanoemulsion (NE) on hake burgers (FB) during 15 days at 4 °C were studied. Fatty acids determined by gas chromatography coupled with mass spectrometry (CG-MS), volatile compounds determined by solid phase microextraction (SPME) coupled with CG-MS, total volatile basic nitrogen (TVBN), and microbial count was measured. ANOVA and DCG tests were performed. After 14 days, significant differences were detected among samples (P ≤ 0.05). FB with EO (EO-FB) and FB with NE containing EO (NEEO-FB) had the highest content of EPA (eicosapentaenoic acid) (191.82 and 198.42 g kg⁻¹) and DHA (docosahexaenoic acid) (107.97 and 110.87 g kg⁻¹, respectively). Also, NEEO-FB had the lowest microbial count (7 log CFU g⁻¹). The incorporation of the oregano essential oil into a nanoemulsion improves the preserving activity in hake fish burgers.     

Effect of antioxidants in combination of VCO nanoemulsion on gel properties and storage stability of refrigerated sardine surimi gel

Impacts of β-glucan–virgin coconut oil (VCO) nanoemulsion containing epigallocatechin gallate (EGCG) and α-tocopherol at levels of 0–3.0 g kg⁻¹ on properties and storage stability of surimi gel were investigated. Augmented breaking force, deformation and fracture constant were obtained in gels containing 2.0 g kg⁻¹ EGCG or 1.0 g kg⁻¹ α-tocopherol (P < 0.05). Expressible moisture content increased as EGCG levels were more than 2.0 g kg⁻¹. Smoother microstructure was observed in gels containing 2.0 g kg⁻¹ EGCG. Whiter gels were obtained when β-glucan–VCO nanoemulsion was incorporated. No change in protein pattern of gels was observed regardless of antioxidant incorporation. Viscoelastic moduli decreased as β-glucan–VCO nanoemulsion was added; however, incorporation of 2.0 g kg⁻¹ EGCG or 1.0 g kg⁻¹ α-tocopherol lowered the decrease in G'. β-glucan–VCO nanoemulsion containing gels had higher likeness scores than the control (P < 0.05). Gels containing EGCG and α-tocopherol at selected levels had the improved oxidative stability and lowered microbial loads.     

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.     

Ethanolic Noni (Morinda citrifolia L.) leaf extract dechlorophyllised using sedimentation process: Antioxidant,antibacterial properties and efficacy in extending the shelf-life of striped catfish slices

Antioxidant and antimicrobial activities of ethanolic noni leaf extract (ENLE) without and with chlorophyll removal by sedimentation method were comparatively investigated. Total chlorophyll content was reduced by 82% in the top fraction (CR-ENLE) collected after 24 h at 4 °C as compared to that of ENLE. Antioxidant and antimicrobial activities were lower in the bottom fraction rich in chlorophyll (Chlo-ENLE) than others (P < 0.05). Based on the microbiological limit, the shelf-life of striped catfish slices pre-treated with 400 mg kg⁻¹ C-R-ENLE was extended to 9 days as compared to the 3 days recorded for the control (without pre-treatment). Slices treated with CR-ENLE had lower lipid oxidation than those treated with ENLE during refrigerated storage (P < 0.05). The sedimentation process was therefore a potential green method for producing ENLE having improved antioxidant and antimicrobial activities without green colour. It can be used as a natural additive for shelf-life extension of fish slices.     

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.     

Investigation of using possibility of grape pomace in wafer sheet for wheat flour substitution

In this study, grape pomace (GP), a by-product consisting of grape skins and seeds rich in dietary fibres and polyphenols, was used in wafer sheets at different concentrations [5.00 (GP5), 10.0 (GP10), and 15.0 g 100 g⁻¹ (GP15)] for the partial replacement of wheat flour (WF) and improve the functionality of wafer sheets. The GP inclusion at concentrations higher than 5.00 g 100 g⁻¹ significantly affected the texture of sheets as well as the flow behaviour of batters, resulting in softer sheets and more viscous batters (P < 0.05). Moisture contents did not significantly change after GP addition (P > 0.05). After the addition of GP, the L* values decreased and the a* values increased, making the wafers darker (P < 0.05). Moreover, under simulated in vitro digestion conditions, the bioaccessibility of total phenolic compounds in saliva, gastric juice, and intestinal juice was significantly higher than control even at the lowest GP concentration (P < 0.05). Regarding sensory properties, only smoothness and crispness were significantly affected by GP addition, and samples were found to be crisper with higher concentrations of GP. In conclusion, it is possible to partially replace the WF in wafers with GP at a concentration of 5.00 g 100 g⁻¹ to develop a product with higher functionality and nutrient content.     

Practical use of β-carotene-loaded nanoemulsion as a functional colorant in sausages made from goat meat surimi-like material

The potential applicability of β-carotene-loaded nanoemulsion (CNE) as a natural colorant in non-smoked sausage made from goat meat surimi-like material (GMS) was elucidated. The effect of CNE content (0–30 g 100 g⁻¹) on the physicochemical characteristic, oxidative stability and β-carotene remaining during cold storage (4 °C) was determined. The higher the CNE, the greater the a*, b* and redness index with the lower L*, and colour likeness score. CNE content had a little impact on the moisture content, a_w and pH of sausages over storage period. However, the expressible drip, breaking force and deformation were largely influenced by the CNE content. All CNE-containing sausages displayed a superior oxidative stability to control. Among CNE-incorporated samples, the lowest lipid oxidation and β-carotene degradation were noticeable in the sausage with 10 g 100 g⁻¹ CNE. Thus, the CNE at 10 g 100 g⁻¹ was a promising functional colorant for emulsion sausage made from GMS.     

Evaluation of antibacterial protein with antioxidant activity from Rahnella aquatilis L103 and its effect on beef during refrigerated storage

A strain, Rahnella aquatilis L103, which was isolated from the soil around the roots of mushrooms, produced antibacterial protein though fermentation. This protein has broad antibacterial spectrum towards gram-positive and gram-negative bacteria. The protein has a significant antioxidant capacity on scavenging ABTS^+· (82.5%, 120 μg mL⁻¹), DPPH^· (64.1%, 600 μg mL⁻¹) and OH^· (60.1%, 750 μg mL⁻¹) as well. The protein was considered to be safe within concentration of 150 μg mL⁻¹ as shown by MTT results and was applied to beef refrigerated preservation. The treatment group presented lower total viable counts (TVC), total volatile basic nitrogen (TVB-N), 2-thiobarbituric acid (TBA), meanwhile, higher sensory score and longer shelf life (2 days) compared with the control group (P < 0.05). The results indicated that the protein under safe concentration was beneficial to beef preservation.     

Comparison of releasing bound phenolic acids from wheat bran by fermentation of three Aspergillus species

Wheat bran was fermented at 28 °C for 7 days under 70% humidity by Aspergillus niger, Aspergillus oryzae and Aspergillus awamori. Total phenolic content (TPC) of the unfermented sample was 1531.5 μg g^?1 wheat bran. After the fermentation of Aspergillus awamori, Aspergillus oryzae and Aspergillus niger, TPC reached 5362.1, 7462.6 and 10 707.5 μg g^?1, respectively. The antioxidant activity in the extractions of fermented wheat bran also increased significantly compared with the unfermented sample (P < 0.05). Aspergillus niger showed the greatest capacity to release bound ferulic acid (416.6 μg g^?1). Aspergillus oryzae and Aspergillus awamori had the advantages of releasing more chlorogenic acid (84.0 μg g^?1) and syringic acid (142.3 μg g^?1), respectively. The destructive effect of Aspergillus niger on wheat bran structure was the strongest, followed by that of Aspergillus oryzae. This effect of Aspergillus niger may be due to its higher cellulase, xylanase, arabinofuranosidase and β‐xylosidase activities. Besides, Aspergillus oryzae possessed higher β‐glucosidase activity, and Aspergillus awamori had higher α‐amylase and feruloyl esterase activities. Aspergillus niger may be the best to release bound phenolic acids in the three Aspergillus species. These will provide the helpful information for understanding mechanism of the fermentation by Aspergillus species releasing bound phenolic in wheat bran.     

Effect of debittering and solid-state fermentation processes on the nutritional content of lupine (Lupinus mutabilis Sweet)

There is a growing interest in vegetable-based sources of proteins. Despite its high nutrient content, lupine has been rarely exploited as a protein source due to the presence of high levels of non-nutritive compounds such as alkaloids, which impart a bitter taste. Here, we evaluated the effect of debittering and solid-state fermentation on the nutritional contents of three lupine varieties (Lupinus mutabilis Sweet). These processes induced significant changes (P < 0.05) in the nutritional composition of the three lupine varieties (INIAP-450, INIAP-451 and Criollo) and increased the protein levels to 644.55 g kg⁻¹ (Criollo variety) and the levels of several constituent amino acids such as valine (54.62 g kg⁻¹), methionine (42.47 g kg⁻¹), isoleucine (59.27 g kg⁻¹) and leucine (76.32 g kg⁻¹). The ether extract of INIAP-450 showed increased levels (up to 244.03 g kg⁻¹); especially, monounsaturated fatty acids (559.78 g kg⁻¹) and polyunsaturated fatty acids (293.17 g kg⁻¹) were observed. The omega-6/omega-3 ratio in the debittered grain oil reached the minimum requirement established for good-quality oils (5/1). However, the levels of other components decreased, showing levels up to 13.04 g kg⁻¹ (total starch) in the Criollo variety, 22.62 g kg⁻¹ (resistant starch) in INIAP-450, 6.53 g kg⁻¹ (potassium) in INIAP-451, 46 g kg⁻¹ (iron) in INIAP-451 and 29.75 g kg⁻¹ (zinc) in INIAP-450.     

Effects of treatment with nisin on the microbial flora and sensory properties of a Greek soft acid-curd cheese stored aerobically at 4 °C

The present study evaluated the use of nisin as an antimicrobial treatment for shelf-life extension of Galotyri, a Greek soft acid-curd cheese, stored aerobically under refrigeration for a period of 42 days. Three different treatments were tested: N0, control sample with no nisin added; N1, 50 IU g⁻¹ nisin; and N2, 150 IU g⁻¹ nisin, the latter two treatments added post-production to the Galotyri cheese. Of all microorganisms enumerated, lactobacilli, lactococci and yeasts were the groups that prevailed in cheese samples, irrespective of antimicrobial treatment. Based primarily on sensory evaluation (appearance and taste) and a microbiological acceptability limit for yeasts (5 log cfu g⁻¹), the use of nisin treatments extended the shelf-life of fresh Galotyri cheese stored at 4 °C by ca. 7 days (N1) and 21 days (N2) with cheese maintaining good sensory characteristics.     

Evaluation of oscillatory and shear strain behaviour for thermo-rheological plasticisation of non-ripened cheese curd: Effect of water,protein, and fat

Non-ripened cheese curd with different dry matter (34.5–47.0 g 100 g⁻¹), protein (13.4–30.4 g 100 g⁻¹), and fat (0.5–25.9 g 100 g⁻¹) contents were produced from pre-acidified milk (citric acid, pH 5.8) with different fat-to-protein ratios (0, 0.18, 0.33, 0.79, 1.60) and different curd cooking times (15 min, 30 min, 85 min). From small angle oscillatory temperature sweep and large strain capillary rheology shear experiments it was deduced that the protein content increases and fat decreases maximal loss tangent and storage modulus. This is discussed in relation to suggested changes in casein micelle voluminosity with temperature. A critical shear stress above which the flow behaviour changes from regular to melt fracture behaviour was observed. This is explained by shear jamming and the frequency dependency of the sol–gel transition.     

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.     

Effect of chitooligosaccharide from squid pen on gel properties of sardine surimi gel and its stability during refrigerated storage

Effect of chitooligosaccharide from squid pen prepared using lipase (COS-L) at various concentrations (0–30 g kg⁻¹) on gel properties of sardine surimi gel was investigated. Breaking force (BF) and deformation (DF) of gel were increased, when COS-L level was increased up to 10 g kg⁻¹ (P < 0.05). Water holding capacity and whiteness of gel were improved with the addition of COS-L than those of control. Gel added with 10 g kg⁻¹ COS-L had denser network with higher likeness score for all sensory attributes, compared to control. When gel incorporated with 10 g kg⁻¹ COS-L was stored at 4 °C, BF, DF and whiteness were maintained during 10 days of storage. Textural properties of surimi gel added with COS-L were higher than those of control throughout storage. Thus, incorporation of 10 g kg⁻¹ COS-L could improve gel properties of sardine surimi gel and retarded the deterioration of gel properties during refrigerated storage.     

Microstructure characteristics of tea seed dietary fibre and its effect on cholesterol,glucose and nitrite ion adsorption capacities in vitro: a comparison study among different modifications

The effects of xylanase–cellulase hydrolysis, ultrasonic modification and enzymatic-ultrasonic treatment on the physicochemical properties, morphological structures and adsorption capacities in vitro of purified fibre (PF) from tea seed were determined. The results showed the ultrasonically treated fibre (UTF) had a higher water-holding capacity (60.15 g g⁻¹), oil-binding capacity (30.42 g g⁻¹), swelling capacity (29.93 mL g⁻¹), emulsification activity (381.36 m² g⁻¹) and emulsification stability (20.20) than PF, enzymatically hydrolysed fibre (EHF) and enzymatic-ultrasonic treated fibre (EUF). The structures of PF, UTF, EHF and EUF were characterised by scanning electron microscope, Laser particle size analyzer, X-ray diffraction, thermogravimetric analysis and Fourier transform infrared spectra. Furthermore, compared with PF, the adsorption capacity of UTF, EHF and EUF for cholesterol, glucose and nitrite ions during simulative gastrointestinal tract was improved to different degrees. This study can provide guidance for the comprehensive utilisation of byproduct of tea seed and designing novel functional dietary fibre.     

Changes in bioactive compounds and their relationship to antioxidant activity in white sufu during manufacturing

In this article, samples of white sufu were collected at different manufacture stages and their content of water‐soluble protein (WSP) and amino nitrogen (AN); the distribution of peptides in WSP and isoflavones, as well as the antioxidant activities, was analysed. Results indicated that the peptides with molecular weight of 500–1000 Da increased 13.09 times from 0.11 to 1.44 g 100 g^?1 dry matter (DM) during the whole manufacturing, while isoflavone glucosides were almost entirely converted to aglycones after ripening for 15 days. Ferric reducing power (FRAP) and 2,2′‐azinobis‐3‐ethylbenzothiazoline‐6‐sulphonic acid radical scavenging activity (ABTS RSA) were significantly increased by 2.80‐ and 1.60‐fold, respectively. Correlation analysis suggested that ABTS RSA was significantly related to WSP (especially for the 500–1000 Da peptides; P < 0.01) and the content of aglycones (P < 0.05), while FRAP was only correlated to WSP (P < 0.05). It is concluded the peptides were the most important components contributing to the antioxidant activities of sufu.     

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.