Effect of total milk solid content adjusted by adding ultrafiltered milk retentate on quality of set mango yoghurt

The quality of set mango yoghurt prepared by varying total milk solids (TMS) level in mango yoghurt mix, by adding 5× ultrafiltered cow skim milk retentate and cow milk cream, was investigated. The water‐holding capacity (WHC) and values of textural attributes of mango yoghurt increased, whereas body and texture and overall acceptability scores decreased significantly (P < 0.05) with increasing TMS level. The optimised product (10.2% TMS level) was compared with conventional mango yoghurt. Acetaldehyde concentration, WHC, values of textural attributes, body and texture, overall acceptability scores and pH were significantly (P < 0.05) higher in optimised compared with conventional mango yoghurt.     

Chicken breast quality – normal,pale, soft and exudative (PSE) and woody – influences the functional properties of meat batters

Three classes (normal, PSE‐like and woody, thirty for per class) of fresh chicken breast meats were selected from a Chinese processing plant. Then, three classes of chicken breast meats were used to prepare meat batters and meatballs. This study investigated the effects of three classes of chicken breast meat on the physicochemical properties, water distribution, protein secondary structures and microstructures of meatballs. PSE‐like and woody meatballs both had lower water holding capacity and textural properties than normal meatballs. Furthermore, the free water mobility and proportion in PSE‐like and woody meatballs were increased (P < 0.05). According to near‐infrared spectroscopy results, the intensity of the 1940‐nm bands of PSE‐like and woody classes both increased. Both PSE‐like and woody meatballs formed more aggregated gel matrices than normal class. PSE‐like and woody classes had higher α‐helix and lower β‐structure contents (P < 0.05). Overall, compared with normal meatballs, PSE‐like and woody meatballs showed inferior functional properties.     

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.     

Effect of some operating variables on the microstructure and physical properties of a novel Kefir formulation

In this work, the rheological and textural properties, water-holding capacity (WHC), syneresis, and microstructure of a novel formulation of Kefir were studied by varying the incubation time and temperature, as well as the ratio of peanut-milk and skimmed-milk. Generally, all the experimental responses resulted to be significantly affected (p < 0.05) by all dependent variables examined. Kefir WHC was not significantly influenced (p > 0.05) by the fermentation temperature.     

Effect of mungbean [Vigna radiata (L.) Wilczek] protein isolates on the microbial transglutaminase‐mediated porcine myofibrillar protein gels at various salt concentrations

This study was performed to investigate the effects of mungbean protein isolates (MPI) as a meat/water binder on the MTGase‐mediated porcine myofibrillar protein (MP) gels at 0.15, 0.3, and 0.45 m salt concentrations. The general property of MP gel was evaluated by pH, cooking loss (CL) (%) and gel strength (gf). Protein–protein interactions among MPI, MTGase, and MP during cooking were also assessed using gel electrophoresis, thermal analysis and microstructure. When salt content was reduced, gel CL (%; P < 0.05) was increased while pH and gel strength (gf) values were decreased (P < 0.05). Addition of MTGase to MP increased pH, CL (%), and gel strength (gf) values, while co‐addition of MTGase and MPI induced synergistic effects on the MP gel strength (gf; ≥0.3 m salt concentration; P < 0.05). In scanning electron micrograph images, increase of salt concentrations made MP gels more swollen and interwoven or conglomerated, regardless of treatment. In conclusion, addition of MPI and MTGase strengthened gel‐forming ability and improved cooking yield of MP gel at salt concentration (≥0.3 m ).     

Improvement of tenderness and water holding capacity of spiced beef by the application of ultrasound during cooking

The aim of this study was to assess the effects of power ultrasound‐assisted (0, 400, 600, 800 and 1000 W, frequency of 20 kHz) cooking (80, 100, 120 min) on spiced beef. The results showed that power ultrasound could significantly increase the salt content (P < 0.05). For water holding capacity, the ultrasonic treatment could significantly reduce the pressure loss and free water content while improving the immobilised water content (P < 0.05). And ultrasonic treatment improved hardness compared with control (P < 0.05). However, the effects on the springiness, the chewiness and the resilience of the spiced beef were not significant (P > 0.05). As for microstructure, the myofibrils of beef were ruptured by ultrasonic treatment along with the Z‐lines leading to the muscle swelling. The results indicated that the application of ultrasound during cooking could effectively promote the penetration of salt, improve the water holding capacity and ameliorate the tenderness of spiced beef.     

Influence of semolina replacement with salmon (Oncorhynchus tschawytscha) powder on the physicochemical attributes of fresh pasta

This study evaluated the influence of the incorporation of salmon (Oncorhynchus tschawytscha) fish powder (SFP) into pasta production and the effect on pasta physicochemical attributes. Four replacement levels were tested (5%, 10%, 15% and 20%) together with a control pasta (100% semolina). The effects on the chemical composition, physical properties (optimal cooking time, cooking loss, water absorption index, swelling index and colour and textural properties (firmness and extensibility) were analysed. The results demonstrated that pasta with SFP had increased protein (12.88–23.40%), lipid (0.46–7.20%), ash (0.39–0.57%) and energy (122.26–161.08 kcal) contents (P < 0.05), increased cooking time (6.30–8.30 min) and cooking loss (4.28–8.02%) compared with semolina control pasta. However, all pasta samples were in the acceptable range (8 g/100 g) for cooking loss. The addition of SFP resulted in significantly decreased swelling index (2.29–1.95), water absorption (105.46–81.62%) and firmness (3.13–1.16 N) (P < 0.05) whilst increasing resistance to uniaxial extension of pasta. Colour parameters indicated comparable brightness between the samples and higher redness values for enriched pasta. Thus, pasta fortified with SFP has the potential to be a technological alternative for the food industry to provide protein-enriched pasta.     

Physicochemical and antioxidant properties of Maillard reaction products formed by heating whey protein isolate and reducing sugars

This study was conducted to investigate the physicochemical and antioxidant properties of Maillard reaction products (MRP) prepared by heating whey protein isolate (WPI) and reducing sugars (glucose and galactose) to 95 °C for different lengths of time (0–6 h). The results revealed that the colour, intermediate products, browning intensity and the antioxidant activities of the MRP increased as the reaction time increased (P < 0.05), whereas the pH value and free amino group content decreased (P < 0.05). Sodium dodecyl sulphate–polyacrylamide gel electrophoresis indicated that the covalently linked conjugates of WPI and sugars were formed. The results indicate that the Maillard reaction could improve the antioxidant capacity of WPI.     

Effects of high hydrostatic pressure on the physicochemical and emulsifying properties of sweet potato protein

The influence of high hydrostatic pressure (HHP) treatment on the physicochemical and emulsifying properties of sweet potato protein (SPP) at various concentrations, e.g. 2%, 4% and 6% (w/v, SPP‐2, SPP‐4 and SPP‐6), was investigated. Significant differences in hydrophobicity, enthalpy of denaturation and solubility were observed (P < 0.05). Emulsifying activity indexes (EAI) of SPP‐2 and SPP‐6 increased at 400 MPa, whereas EAI of all SPP significantly decreased at 600 MPa (P < 0.05). Emulsion stability (ESI) was significantly decreased for SPP‐2 and SPP‐6, while increase in ESI was observed for SPP‐4 above 200 MPa (P < 0.05). SPP‐2 emulsions showed sharp decrease in apparent viscosity with pressure increase, while pseudo plastic flow behaviour was not changed for all of emulsions. Sporamins A and B were well‐adsorbed in pressurised emulsion without displacement. These results suggest that HHP treatment could be used to modify the physicochemical and emulsifying properties of SPP.     

Effect of bamboo salt on the physicochemical properties of meat emulsion systems

This study was conducted to determine the effects of various bamboo salts on meat batter. To accomplish this, three different batters were prepared and compared: CON, which was prepared with NaCl, BS-2, which was prepared with bamboo salt that was baked twice, BS-9, which was prepared with bamboo salt that was baked nine times. The pH of both the uncooked and cooked BS-2 and BS-9 was higher than that of the CON (P < 0.05). The emulsion stability, cooking yield, water holding capacity (WHC) and apparent viscosity of BS-2 and BS-9 were higher than those of CON. The correlation coefficient between the viscosity value and WHC was high and positive (R² = 0.672). The hardness of all treatments was significantly increased with increased cooking temperature (P < 0.05). The hardness, gumminess and chewiness of CON were higher than that of BS-9 and BS-2. The overall acceptability score between CON and BS-9 was significantly different (P < 0.05). The bamboo salts effectively improved the physicochemical properties of the meat batter.     

Evaluation of various salt levels and different dairy proteins in combination with microbial transglutaminase on the quality characteristics of restructured pork ham

The objective of this study was to evaluate the quality characteristics of restructured pork hams (RH) manufactured with various salt levels (0.5%, 1.0%, and 1.5%) and different dairy proteins (sodium caseinate, SC and whey protein isolate, WPI; 1.0%) in combination with microbial transglutaminase (MTGase; 0.3%). Reduced‐salt (0.5% and 1.0%) RH resulted in reductions of moisture contents (%), textural springiness, cooking yield and most sensory preferences (P < 0.05). When dairy proteins in combination with MTGase were incorporated into the manufacture of RH, SC with MTGase was shown to reduce cooking loss (CL, %) and to increase the textural springiness and chewiness of RH, whereas WPI with MTGase increased textural springiness and chewiness, as well as the shear value of RH (P < 0.05). On the contrary, MTGase with dairy proteins improved the sensory preferences of reduced‐salt (1.0%) RH to give it similar sensory properties to those of the regular‐salt (1.5%) RH controls (CTL) (P > 0.05). The findings of this study demonstrated that the combination of 1.0% dairy proteins and 0.3% MTGase could affect improvements in the functional, textural and sensory properties of reduced‐salt (1.0%) RH.     

Variations in lipid and fatty acid contents in different body parts of Black Sea whiting,Merlangius merlangus euxinus (Nordmann, 1840)

Whiting is a commercially important fish species of the world. This study demonstrates monthly variations in lipid and fatty acid (FA) contents of muscle, liver and roes of Black Sea whiting, Merlangius merlangus euxinus. Significant changes occurred in lipid contents between months (P < 0.05) with the highest values representing in liver 33.8–64.5%. Total polyunsaturated fatty acids (PUFA) in all groups were higher than total saturated and monounsaturated FAs with significant variations between months (P < 0.05). The highest PUFA of muscles, livers and roes were 60.0, 45.9 and 50.9%, respectively. The main FA was docosahexaenoic acid (DHA) of muscle tissue and roes, while oleic acid was the major FA in livers. Although about 164–357 g in muscle tissue or 224–392 g of whiting roe are necessary to consume to cover 1 g day^?1 of eicosapentaenoic acid (EPA)+DHA for a healthy diet, only as low as 5.5–10.0 g of liver would be enough to cover the same amount of daily EPA+DHA requirement. The results indicated that whiting livers constitute a rich and underexploited source of polyunsatured FAs. Furthermore, the results may aid further research on the nutritional studies, the physiology and stock management of whiting species.     

Protein hydrolysates of salted duck egg white improve the quality of Jinga Shrimp (Metapenaeus affinis)

The influence of protein hydrolysates of salt duck egg white (PHSDEW) hydrolysed by acid protease on the quality of Jinga Shrimp (Metapenaeus affinis) was analysed. Shrimp immersed in 5% PHSDEW with degree of hydrolysis (DH 3%) had the highest values of cooking yield, water retention, moisture and texture with the lowest cooking loss when compared to which immersed in 0.4% NaCl, 3.5% mixed phosphates and other PHSDEW with different DH (1%, 2% and 5%) (P < 0.05). This treatment made muscle fibres retain the most appropriate compact and regular microstructure and improved the thermal stability of shrimp protein as well (P < 0.05). SDS‐PAGE protein patterns revealed shrimp protein would dissolve out during immersion, while only could PHSDEW infiltrate into shrimp muscle. It suggested PHSDEW would be developed as a new type of water retention agent replaced phosphate used in shrimp or other seafoods, which will decrease the waste of salt duck egg white.     

The impact of desmin on texture and water‐holding capacity of ice‐stored grass carp (Ctenopharyngodon idella) fillet

The objective of this work was to analyse the role of desmin in texture softening and water‐holding capacity (WHC) of ice‐stored grass carp fillet. Results indicated that shear force of the fillet decreased sharply within 3 days, while drip loss increased during the whole ice storage. Water mobility and distribution were measured by low‐field ¹H NMR T₂ relaxation that revealed a positive correlation (P < 0.01) between WHC and the mobility of the immobilised water (T₂₁ relaxation time). Meanwhile, negative correlation could be established between intact desmin and drip loss (P < 0.01). Intact desmin was extremely correlated with shear force (P < 0.01) and positively correlated with calpains activity (P < 0.05). This study demonstrated that the degradation of desmin was involved in the mobility of the myofibrillar water and softening of grass carp fillet during ice storage. Furthermore, calpains autolysis seemed to result in desmin degradation.     

Sensory characteristics and storage quality indicators of surimi franks nutritionally enhanced with omega‐3 rich flaxseed oil and salmon oil

Surimi franks were fortified with flaxseed or salmon oil at 2 g/100 g sample, franks without added oil served as a control. Thiobarbituric acid reactive substances values were highest (P < 0.001) in salmon oil franks; however, these values did not change over the 21‐day storage period regardless of frank type (P > 0.05). Frank pH decreased over time (P = 0.011) for all frank types. There were differences in textural properties between frank types (P < 0.05), with the flaxseed franks being softer and less gummy, cohesive and chewy than the control franks. Participants (n = 79; age 18–35) evaluated visual appeal, colour, aroma, texture, flavour and acceptability on a hedonic scale; there were no differences (P > 0.05) between franks. Fifty‐four panellists reported consuming sausage on a weekly to monthly basis, and most (50/79) indicated interest in purchasing this type product. The surimi franks were accepted by young adult consumers, which may indicate market potential of these types of products.     

Gelation properties of goose liver protein recovered by isoelectric solubilisation/precipitation process

Isoelectric solubilisation/precipitation (ISP) process was applied to goose liver (GL) for protein extraction. The gelation properties of proteins extracted by acid processes (ACP, pH 2.0, 2.5 and 3.0) and alkaline processes (ALP, pH 11.0, 11.5 and 12.0) were estimated, where the unextracted ground GL was set as the control. Nearly 58.39~79.00% of GL proteins were recovered by ISP treatments. High molecular weight (100~250 kDa) proteins were found to be partially hydrolysed by ACP, while few changes in proteins occurred during ALP. As evidenced by rheological and textural measurements, ALP proteins formed gels with high elasticity and superior texture, whereas ACP proteins had inferior gelation properties. Moreover, ALP proteins were able to form a highly interconnected and homogeneous three‐dimensional microstructure. Predominantly, gels produced by 11.0 had optimal texture and the lowest cooking loss (P < 0.05). These results suggested that the ISP process (ALP) is a potential method to improve the economic value of GL.     

High-Pressure Pretreatment to Improve the Water Retention of Sodium-Reduced Frozen Chicken Breast Gels with Two Organic Anion Types of Potassium Salts

The effect of high-pressure pretreatment (HPP, 100–300 MPa) before heating on the water holding capacity (WHC) and cooking loss (CL) of sodium-reduced (1.35% NaCl) frozen chicken breast gels with the organic anion types potassium lactate (KL-gel) and potassium citrate (KC-gel) was investigated. The results showed that 100–300 MPa could significantly decrease the CL of both gels, and 200 MPa increased the WHC of the KC-gel (P?<?0.05). HPP could decrease the storage modulus (G′) of meat batters, increase the thermal stability of their proteins, facilitate gelation with a dense and uniform microstructure, and immobilize free water, thus improving the gel’s water retention. The water retention of the pressurized sodium-reduced gel varied with the organic anion types of salts. The water retention was better with pressurized KC-gel than with KL-gel, resulting from higher pH and thermal stability of the batters. These results indicate that proper HPP could improve the water retention of sodium-reduced meat gels with organic potassium salts, thus increasing the economic benefit and properties of sodium-reduced products from frozen meat.     

The use of selected hydrocolloids to enhance cooking quality and hardness of zero‐salt noodles

The effects of table salt (TS) and hydrocolloids on water‐holding capacity, optimum cooking time, cooking qualities, pH and textural properties of noodles were investigated. TS, xanthan gum (XG), carrageenan (CRG), Arabic gum (AG) and locust bean gum (LBG) were added at 0.5%, 1.0%, 1.5% and 2.0% of flour weight. XG, CRG and LBG contributed to significantly (P < 0.05) higher water‐holding capacity of dough and firmer texture, but significantly (P < 0.05) lower cooking loss than zero‐salt noodles (ZSNs) and white‐salted noodles (WSNs). Hydrocolloids contributed in shorter optimum cooking time than ZSNs. Springiness of noodles was not significantly (P > 0.05) affected by increment of TS and hydrocolloids. TS1.5, ZSN‐XG1.5, ZSN‐XG2.0 and ZSN‐CRG1.5 had significantly (P < 0.05) higher cooking yield than ZSNs. The increment of TS and hydrocolloids had significantly (P < 0.05) increased the pH values of noodles. ZSN‐XG2.0, ZSN‐CRG1.5 and ZSN‐LBG1.5 may be useful to enhance ZSNs due to the better noodles qualities than ZSNs.     

Relevance of collagen solubility and gelatinolytic proteinase activity for texture softening in chilled grass carp (Ctenopharyngodon idellus) fillets

The aim of the present study was to investigate the underlying mechanisms of softening texture in chilled grass carp filletsunderpinning collagen solubility, gelatinolytic proteinase activity and physicochemical parameters. Acid-soluble collagen (ASC) and heat soluble collagen (HSC) increased markedly, while a significant decline was detected in total collagen and insoluble collagen (ISC) during the first 3 days of storage, coinciding with a loss of shear force and water-holding capacity (WHC) (P < 0.05). Moreover, the activity of gelatinolytic proteinases was gradually activated and reached the peak at day 3 (P < 0.05). Pearson coefficient analysis showed that gelatinolytic proteinase activity revealed a significant correlation with collagen solubility. Total collagen, ASC, ISC and HSC were significantly correlated with shear force and WHC. Our study clarified that the increase of collagen solubility by gelatinolytic proteinases played an important role for texture softening in the early stage of chilled grass carp fillets.     

Effects of Agaricus bisporus on gel properties of chicken myofibrillar protein

The gel-forming ability of myofibrillar protein (MP) is highly correlated with the characteristics of emulsified meat products. Incorporation of Agaricus bisporus (Ab) powder into MP gels may enhance its gel properties to facilitate the development of a novel and safe meat product. Therefore, this study investigated the effects of Ab powder on gel strength, water holding capacity (WHC), texture, rheological behaviour, LF-NMR spin–spin relaxation (T₂), microstructure and protein secondary structure of the MP gel system. The results indicated that the gel strength, WHC, G' value and G" value were significantly improved when the addition of Ab powder increased from 0% to 6% (P < 0.05). Meanwhile, the T₂ relaxation time was shortened, and free water was transformed into immobilised water. The texture of the gel was improved when 1%–4% Ab powder was added compared to the control. Furthermore, Ab filled in the gel network and promoted the unfolding of MP α-helix and the formation of MP β-sheet during the thermal denaturation of MP, leading to a dense aggregated network structure. The study suggested that Ab could be a promising ingredient in improving chicken MP's gel properties and developing fat-reduced meat products.