Water Holding Capacity Values Research Articles

Physicochemical Properties and Microstructure of Mixed-species Surimi Made from Decapterus sp. and Priacanthus sp.

The surimi industry plays a substantial role in bolstering Indonesia’s fishing sector. The collapse of the majority of surimi companies can be attributed to the government limitation on trawling, which served as the primary source of demersal fish utilized in surimi processing. This restriction resulted in a significant shortage of raw material for industry. Therefore, it is imperative to explore alternate fish species that can serve as viable raw materials for the production of surimi. Alternative fish species are needed as raw materials for surimi. The objective of this work was to investigate the physicochemical characteristics and microstructure of surimi produced from two distinct Indonesian fish species: Decapterus sp., a pelagic species, and Priacanthus sp., a demersal species. Five ratios of Decapterus sp and Priacanthus sp; 1:0 (F1: control 1), 3:1 (F2), 1:1 (F3), 1:3 (F4), and 0:1 (F5: control 2) were tested. The proximate composition showed that the addition of Decapterus sp. to the formula increased the protein and fat content of mixed surimi. The formula F4 showed the highest value for almost all textural profile parameters; there were springiness, cohesiveness, gumminess, chewiness, and resilience. The same result also presented in the gel strength, F4 also has the highest value. The Water Holding Capacity value was low, and it showed no difference between all formulas. The whiteness value was in the range of 66-68, and it showed no difference between all formulas. Protein patterns showed no myosin heavy chain in all formulas. Microstructure analysis showed that only F5 (control 2) was compact and denser, but the other formulas (F1, F2, F3, and F4) showed a large number of loose and porous structures. In the microbial analysis, all formulas showed the Total Plate Count value ( 6 x 105 cfu/g) was under the maximum acceptable value (107 cfu/g). The findings of the study indicated that the mixed-surimi, consisting of Decapterus sp and Priacanthus sp at a ratio of 1:3, exhibited the highest level of gel strength. In conclusion, Decapterus sp has the potential to serve as a viable raw material when combined with Priacanthus sp.

Effects of packaging methods and temperature variations on the quality and microbial diversity of grouper (Epinephelus Lanceolatus) during cold storage

Microbial growth and its metabolism are the primary reasons for fish spoilage. In this study, the effects of temperature fluctuations and modified atmosphere packaging (MAP) on the quality and microbial diversity of grouper (Epinephelus lanceolatus) during cold storage were investigated. Fish fillets were packed in air packaging (AP), vacuum packaging (VP), MAP1 (40% CO2/55% N2/5% O2), and MAP2 (60% CO2/35% N2/5% O2), and stored at T1 (4 °C) and T2 (4–8 °C temperature fluctuations), respectively. Total viable counts (TVC), psychrophilic bacteria count, Pseudomonas count, and H2S-producing bacteria count all increased during cold storage. Pseudomonas, Serratia, and Carnobacterium were the dominant genera in AP, VP, and MAP2 at T1 storage, with relative abundances of 82.7%, 54.5%, and 57.3%, respectively. Temperature fluctuations accelerated the spoilage process of the grouper, and increased the relative abundance of Serratia in the samples, but had less effect on the composition of these spoilage bacterial members. The microbial community was more affected by the different gas atmospheres. MAP inhibited the growth of Pseudomonas and increased the relative abundance of Carnobacterium and Psychrobacter in the samples. Low temperature and MAP effectively suppressed the rise of pH, total volatile basic nitrogen (TVB-N), trimethylamine (TMA), thiobarbituric acid reactive substances (TBARs), and K values and maintained the water holding capacity (WHC) and sensory quality of the samples. Grouper had the longest shelf life under MAP2-T1 treatment. The MAP2-T1 samples maintained lower levels of TVB-N (151.8 mg/kg), TMA (7.6 mg/kg), TBARs (0.90 mg MDA/kg), and K value (48.5%) and higher levels of WHC (77.6%) on the 18th day, with a lower degree of spoilage compared to other samples.

Pumpkin (Cucurbita pepo L.) Pulp Flour as a Source of Dietary Fiber: Chemical, Physicochemical and Technological Properties

In this study, the characteristic properties of pumpkin pulp flour (PPF) obtained from the waste of the pumpkin seed production were determined. The pulp parts of the de-seeded and peeled pumpkins were used for this purpose. Proximate composition, total dietary fiber (TDF), insoluble dietary fiber (IDF), soluble dietary fiber (SDF), mineral content, amino acid content, β-carotene content, pH, color, glass transition temperature (Tg), water holding capacity (WHC), oil holding capacity (OHC), swelling capacity (SC), emulsion stability (ES) and emulsion activity (EA) values of PPF were determined. PPF had a low lipid content (0.72±0.06%) and a high ash content (8.34±0.19%). The pH, Tg, TDF, IDF, SDF, WHC, OHC and SC values are 5.61±0.01, 19.19±1.86°C, 26.13±0.17%, 19.82±0%, 6.31%±0.35, 12.91±0.40 g/g, 3.74±0.10 g/g, 12.48±0.57 mL/g, respectively. PPF were a rich source of glutamic acid, glycine, and aspartic acid, and contains high levels of potassium among major elements, and iron among minor elements.

Effects of low-frequency magnetic field on solubility, structural and functional properties of soy 11S globulin.

Soy 11S globulin has high thermal stability, limiting its application in the production of low-temperature gel foods. In this study, the low-frequency magnetic field (LF-MF, 5 mT) treatment (time, 30, 60, 90, and 120 min) was used to improve the solubility, conformation, physicochemical properties, surface characteristics, and gel properties of soy 11S globulin. Compared with the native soy 11S globulin, the sulfhydryl content, emulsifying capacity, gel strength, water-holding capacity, and absolute zeta potential values significantly increased (P < 0.05) after LF-MF treatment. The LF-MF treatment induced the unfolding of the protein structure and the fracture of disulfide bonds. The variations in solubility, foaming properties, viscosity, surface hydrophobicity, and rheological properties were closely related to the conformational changes of soy 11S globulin, with the optimum LF-MF modification time being 90 min. LF-MF treatment is an effective method to improve various functional properties of native soy 11S globulin, and this study provides a reference for the development of plant-based proteins in the food industry. © 2024 Society of Chemical Industry.

A comparison of the quality of plain yogurt and its analog made from coconut flesh extract

The aim of this study was to compare the quality of plain yogurt made from cow milk (n = 10) and its plant-based analog made from coconut flesh extract (n = 14). Coconut yogurt alternatives were divided into 2 experimental groups based on differences in their color, which were noted after the packages had been opened. The first group included products with a typical white color (n = 8), and the second group comprised products with a grayish pink color (n = 6) that developed as a result of oxidative processes. In comparison with its plant-based analog, plain yogurt was characterized by higher values of lightness (L*), yellowness (b*) and chroma (C*), higher titratable acidity, a higher content of retinol and α-tocopherol, higher nutritional value of fat, and lower values of water-holding capacity (WHC) and redness (a*). Plain yogurt had lower volatile acidity than its plant-based analog with a grayish pink color. A comparison of yogurt analogs with different colors revealed that the product with a grayish pink color was characterized by a lower value of L*, and higher values of a*, b*, C*, and pH. An analysis of its fatty acid profile demonstrated that it also had a higher proportion of C14:0 and C18:1 cis-9; higher total monounsaturated fatty acids content; a lower proportion of C10:0, C12:0, and C18:2; a lower total content of polyunsaturated fatty acids (PUFA) and essential fatty acids; and a lower ratio of PUFA to saturated fatty acids. The yogurt analog with a grayish pink color had a lower total content of tocopherol isoforms than the remaining products. The yogurt analog with a white color had the highest WHC and γ-tocopherol content. Consumers should be aware of the fact that coconut yogurt alternatives may have nonstandard quality attributes. The differences between such products and yogurt made from cow milk should be explicitly communicated to consumers so that they could make informed purchasing decisions.

Optimization of cold plasma combined treatment process and its effect on the quality of Asian sea bass (Lates calcarifer) during refrigerated storage.

Cold plasma exhibits broad applicability in the realm of fish sterilization and preservation. The combination process of plasma-activated water and dielectric barrier discharge (PAW-DBD) was optimized, and its disinfection effects on bass fillets were studied. The best conditions for disinfection of PAW-DBD were as follows. Bass fillets were soaked in PAW for 150 s, and then treated by DBD system at 160 kV for 180 s. The total viable count (TVC) reduced by 1.68 log CFU g-1 . On the 15th day of refrigerated storage, TVC of PAW-DBD group was 7.01 log CFU g-1 , while the PAW and DBD group exhibited a TVC of 7.02 and 7.01 log CFU g-1 on day 12; the TVC of the control group was 7.13 log CFU g-1 on day 6. The sensory score, water-holding capacity, and 2-thiobarbituric acid reactive substance values of the PAW-DBD group were significantly higher than those of PAW and DBD group (P < 0.05), whereas the TVC, Pseudomonas spp. count, and pH of the group were significantly lower (P < 0.05) during refrigerated storage. PAW-DBD treatment can enhance the disinfection effect, maintain good quality, and extend the storage period of bass fillets. © 2023 Society of Chemical Industry.

Quality Evaluation of Chicken Sausage Incorporated with Andaliman Fruit Powder as Natural Preservatives at Cold Storage

This research was conducted to evaluate the quality of chicken sausage mixed with Andaliman Fruit Powder (AFP) in cold storage. The study was conducted using a completely randomized factorial design with the addition of AFP (A) as factor I consist of Ao = control (0%), A1 = 0.5%, A2 = 1.0%, and A3 = 1.5%, and storage time at cold temperatures (10 ± 2°C) (S) as factor II consist of So = 0 days, S1 = 7 days, S2 = 14 days, and S3 = 21 days. The sausages were packaged in vacuum plastic packaging. The addition of AFP significantly (p<0.01) decreased the cooking loss and Free Fatty Acids (FFA) of sausages, but increased the Water Holding Capacity (WHC), texture, organoleptic values of tenderness, texture, juiciness, and overall acceptability of sausages. During storage there was a significant increase (p<0.01) in the FFA, texture, WHC, but the organoleptic values of texture, elasticity, juiciness, and overall acceptability were not significantly different (p>0.01) during storage. The interaction between the addition of andaliman fruit powder and storage time only had a significant effect (p<0.01) on the WHC value of the sausages. From this study it was concluded that 1.5% of AFP could be used effectively to maintain the quality of sausages for 21 days of storage, while sausages without the addition of AFP could only maintain the quality for 7 days of storage at cold temperatures.

Drying Technique Providing Maximum Benefits on Hydrogelling Ability of Avocado Seed Protein: Spray Drying.

The current study focused on creating natural hydrogels consisting of mixtures of avocado seed proteins dried with different techniques and locust bean gum. Proteins were extracted from avocado seed by alkali and isoelectric precipitation methods. Avocado seed proteins were dried by five different drying methods, namely ambient drying, oven drying, vacuum drying, freeze drying, and spray drying. FT-IR spectra were used to analyze the chemical structure of proteins dried using various techniques. Additionally, hydrogel models were constructed in the presence of avocado seed proteins and locust bean gum to clarify the effect of drying techniques on their hydrogelling ability. The impact of drying techniques on the functional behavior of hydrogels was notable. The maximum water holding capacity values were detected in the hydrogel system containing spray-dried proteins (93.79%), followed by freeze-dried (86.83%), vacuum-dried (76.17%), oven-dried (72.29%), and ambient-dried (64.8%) counterparts. The swelling ratio was 34.10, 33.51, 23.05, 18.93, and 14.39% for gels in the presence of freeze-dried, spray-dried, vacuum-dried, oven-dried, and ambient-dried proteins, respectively. Additionally, the desirable values for the amount of protein leaking from the systems prepared using spray-dried (7.99%) and freeze-dried (12.14%) proteins were obtained compared to others (ambient-dried: 24.03%; oven-dried: 17.69%; vacuum-dried: 19.10%). Superior results in terms of textural properties were achieved in hydrogel models containing spray-dried and freeze-dried proteins. In general, hydrogel models exhibited elastic behavior rather than viscous properties; however, the magnitudes of elasticity varied. Furthermore, the success of gels containing hydrogel models containing spray-dried protein and locust bean gum in the bioactive compound delivery system was obvious compared with protein ones alone.

Carcass composition and physicochemical and sensory attributes of breast and leg meat from native Mexican guajolote (Meleagris g. gallopavo) as influenced by sex.

The aim of the study was to compare carcass composition and physicochemical and sensory attributes of breast and leg meat from native Mexican guajolote (Meleagris g. gallopavo) as influenced by sex. For this, slaughter weight and carcass characteristics of male () and female () guajolotes raised traditionally under extensive systems with similar housing and feeding conditions were recorded. Also, physical characteristics, proximate composition, the fatty acid profile, and sensory attributes were determined in breast and leg meat using standard procedures. The results showed that males had higher () slaughter weight, hot and cold carcass weights, and dressing percentage, as well as carcass part weights, while females had higher () abdominal fat weights than males. The lightness (), yellowness (), and drip loss values of breast meat, as well as redness () and water-holding capacity values of leg meat, were significantly () influenced by sex. Male breast meat had higher () moisture content, crude protein, erucic acid (C22:1n9), MUFAs (total monounsaturated fatty acids), UFAs (unsaturated fatty acids), DFAs (desirable fatty acids), UFA SFA (total saturated fatty acid) ratio, PUFA (total polyunsaturated fatty acid) SFA ratio, and chewiness scores than females. Likewise, leg meat from males showed higher () ash content, myristic acid (C14:0), palmitic acid (C16:0), stearic acid (C18:0), oleic acid (C18:1n9c), palmitoleic acid (C16:1n7), SFAs, OFAs (odd fatty acids), thrombogenic index, and atherogenic index, whereas females had high fat content. In conclusion, it would be suggested that, from a nutritional point of view, the meat from male guajolotes was preferable to the meat from females.

Changes of quality in yoghurt produced under magnetic field effect during fermentation and storage processes

In this study, the changes in pH, titratable acidity, and organic acid contents of yoghurts produced under three different magnetic field intensities were investigated during the fermentation period. In addition, the yoghurts were stored for 15 d and changes in the physicochemical, microbiological, and sensory qualities of the yoghurts were investigated. During fermentation, the pH values of all samples decreased while titratable acidity and organic acid contents increased. During storage, the pH, firmness, consistency and syneresis values, and acetaldehyde, diacetyl, and acetoin contents of the samples decreased, while titratable acidity, cohesiveness, viscosity index, water-holding capacity values, and organic acid (except pyruvic acid) and ethanol contents increased. As a result of this study, it was found that yoghurts produced under the effect of a magnetic field with an intensity of 180 μT were of higher quality in terms of physical, chemical, microbiological, and sensory criteria compared with other samples.

Comparison of Dietary Fiber Characteristics Prepared from Cassava Pulp Using Acid-Heat Treatment and Extrusion Process

Cassava pulp is used to develop dietary fiber from prospective local resources to boost its added value and applications. Extrusion and an acid-heat treatment were used to alter cassava pulp into nutritional fiber. The goal of this study was to characterize the chemical compositions, physical-chemical functional features, and yield of dietary fiber products produced by the extrusion and acid-heat processes. Total dietary fiber (TDF) content was 89.24%, starch content was 9.7%, water holding capacity (WHC) was 12.07 g/g, oil holding capacity (OHC) was 3.99 g/g, swelling capacity (SC) was 17.8 ml/g, bulk density (BD) was 0.2 g/ml, and yield was 50% for the dietary fiber produced by the acid-heat treatment. While the extrusion process produced dietary fiber with TDF content of 50.86%, starch content of 47.28%, WHC of 9.96 g/g, OHC of 0.81 g/g, SC of 12.99 ml/g, BD of 0.6 g/ml, and a yield of 90%. Acid-heat treatment was successful in eliminating starch constituents, raising TDF, and raising WHC and OHC values. The extrusion procedure did not raise TDF or OHC and could not eliminate components of starch, however, it might increase WHC by swelling the starch granules.

Physical, chemical, and microbiological evaluation of sausages produced with chicken meat affected by deep pectoral myopathy

The purpose of the present study was to characterize the chemical composition, lipid oxidation, and physical characteristics of fresh sausages produced with meat from the pectoralis major muscle affected by deep pectoral myopathy. For the characterization of myopathy, samples were collected from broiler chickens slaughtered between 42- and 46-days old in a slaughterhouse in the state of São Paulo. The experiment consisted of samples from pectoralis major muscle of birds affected or not by DPM (normal-absence of myopathy and DPM category 3-progressive degeneration of the pectoralis minor with a greenish appearance). After classification of the samples, a part of raw products with the pectoralis minor removed, was submitted to microbiological and physical analyses for the characterization of DPM. Afterward, only the pectoralis major muscle was used to manufacture fresh sausages and 2 groups were established. The evaluated parameters were: color, pH, water-holding capacity (WHC), cooking loss (CL), shear force (SF), water activity (Aw), and chemical composition. Meat pH was higher (P < 0.05) in meats with DPM, however, WHC values were lower (71.92%), which made CL value increase (25.31%). In addition, the coloring increased and the technological characteristics of raw breasts were less favorable with the presence of DPM. All fresh sausages' color (except a* higher control group), pH, and Aw values were higher in DPM group. No effect on SF values was observed between fresh sausages. In chemical composition, only protein content increased in fresh sausages with DPM. Microbiological analyses did not indicate bacterial contamination of raw samples and fresh sausages. Data obtained in the present study suggest fresh sausages produced with breasts affected by DPM are a viable alternative and may confer more favorable qualitative characteristics to sausages than the raw marketed meat.

A comparative study on the physicochemical characteristics and protein digestibility of tofu induced by magnesium chloride or combined with transglutaminase

SummaryIn this study, tofu was prepared through the addition of transglutaminase (TGase) for pre‐crosslinking at varying durations (1, 2 and 3 h), followed by the addition of magnesium chloride (MgCl2) to soymilk. The physicochemical properties and protein digestibility were analysed. Results indicated that, with the prolongation of TGase pre‐crosslinking time, the zeta‐potential absolute value and the average particle size of soymilk increased gradually. In contrast, the pH value remained unchanged (P &gt; 0.05), suggesting that the colloidal stability of soymilk improved with TGase treatment. Both the water‐holding capacity (WHC) and gel strength of tofu gels exhibited a first increasing and then decreasing trend with prolonged pre‐crosslinking time. Notably, the highest WHC and hardness values of tofu gels prepared by adding MgCl2 after pre‐crosslinking with TGase for 1 h were 96.5 ± 0.5% and 363.9 ± 28.3 g, respectively. Subsequently, in vitro simulated gastrointestinal digestion of tofu samples prepared under this condition was conducted to determine changes in soluble protein content, small peptide content and protein hydrolysis spectrum. Gastric and intestinal digestion phases were the primary stages of protein hydrolysis, and the bioavailability of proteins in TGase+MgCl2‐induced tofu was higher than in MgCl2‐coagulated tofu. Therefore, tofu prepared through TGase pre‐treatment was more conducive to soybean protein digestion and absorption.

The physical and structural properties of acid–Ca2+ induced casein–alginate/Ca2+ double network gels

The design of protein or polysaccharide interpenetrating network gels according to their physicochemical properties is required to obtain the desired properties of hydrogels. In this study, a method was proposed to prepare casein–calcium alginate (CN–Alg/Ca2+) interpenetrating double-network gels by the release of calcium from a calcium retarder during acidification to form calcium–alginate (Alg/Ca2+) gel and casein (CN) acid gel. Compared with the casein–sodium alginate (CN–Alg) composite gel, the CN–Alg/Ca2+ dual gel network with an interpenetrating network gel structure has better water-holding capacity (WHC) and hardness. The rheology and microstructure results showed that the dual-network gels of CN and Alg/Ca2+ induced by gluconic acid–δ-sodium (GDL) and calcium ions were the network structure of the Alg/Ca2+ gel, which was the “first network”, and the CN gel, which was the “second network”. It was proven that the microstructure, texture characteristics, and WHC of the double-network gels could be regulated by changing the concentration of Alg in the double-network gels and that the 0.3 % CN–Alg/Ca2+ double gels showed the highest WHC and firmness values. The aim of this study was to provide useful information for the preparation of polysaccharide–protein mixed gels in the food industry or other fields.

The Effect of Sodium Bicarbonate Injection on the Physico-Chemical Quality of Post-Harvest Trout.

The muscle hardness of fish is an important parameter associated with meat quality, and the post-mortem decrease in the pH of fish tissue pH affects its physical properties. We hypothesized that maintaining a high pH in fish tissue after death would prevent protein denaturation and consequent textural deterioration. This study aimed to determine the effectiveness of sodium bicarbonate (SBC) injections in preventing tissue softening caused by low pH after death in trout. We injected varying molar concentrations of SBC in rainbow trout (Oncorhynchus mykiss; 0 M, 0.5 M, 0.75 M, and 1 M) after harvest, and the product quality was assessed at 0, 24, 48, 72, and 96 h of ice storage. Quality was evaluated using proximate analyses for color, pH, water holding capacity (WHC), texture profile, and rigor index. The 0 M group had the lowest pH, and the 0.75 M group had the highest pH at all time points during storage. We observed improved tissue texture during storage in fish treated with 0.75 and 1 M SBC. The texture profile analysis showed higher hardness, frangibility, and stickiness in the tail than in the other regions. These varying results can be explained by significant differences between parts of the fish and sampling point selection. We also observed the highest pH and WHC values in the groups injected with 0.75 and 1 M SBC during storage.

Effect of oleaster (Elaeagnus angustifolia L.) flour addition combined with high-pressure homogenization on the acidification kinetics, physicochemical, functional, and rheological properties of kefir.

In this study, the effects of peeled oleaster flour (OF) addition (0.5% and 1%) with high-pressure homogenization (HPH) at 100 MPa on acidification kinetics, physicochemical, functional, and rheological properties of kefir made from bovine whole milk were investigated. The fermentation kinetic parameters such as Vmax and T f decreased by 23.63% and 20%, respectively, with 1% OF and application of HPH. The combined use of two treatments had a positive effect on Lactobacillus and Lactococcus counts, reaching a maximum of 9.63 and 9.31 log cfu/mL, respectively. Also, total phenolic contents and antioxidant activity reached maximum values of 85.31 mg GAE/g and 17.22%, respectively. The ΔE value was more limited with HPH. The maximum firmness and water-holding capacity values were determined in the sample produced with 1% OF and application of HPH. Rheological analysis revealed that all kefirs exhibited shear thinning behavior, and the Ostwald-de-Waele (R 2 > .99) model was suitable to describe the rheological behavior of all kefir samples. The highest viscosity (0.049 Pa.s, at 50/s shear rate) and consistency index (1.115 Pa.sn) were observed in kefir with 1% OF and application of HPH. Kefir samples were characterized as weak gel behavior because storage modulus (G') was much greater than loss modulus (G") and the power-law model was used to characterize the viscoelasticity. The overall quality assessment indicated that the improvement of the fermentation process and the enhancement of textural and functional properties of kefir samples could be achieved with the addition of 1% OF and application of HPH.

Physical quality of beef sausage using porang flour as a substitute for tapioca flour

The aim of this study was to evaluate the physical quality of beef sausage using porang flour as a substitute for tapioca flour. The research material used beef (lean), tapioca flour, and glucomannan flour (porang). The sausage formula was the ratio of tapioca flour to porang flour which consisted of 10:0 (P0); 8:2 (P1); 6:4 (P2); 5:5 (P3); 4:6 (P4); 2:8 (P5), and 0:10 (P6) ratios. Beef sausage parameters included pH, cooking loss, water holding capacity (WHC), and tenderness. Data analysis used Unidirectional ANOVA and continued with Duncan’s test if there were significant differences between the treatments. The results of the study showed that there were differences in pH, WHC, and tenderness (P<0.01), but the cooking loss of beef sausage was not significantly different (P>0.05) among treatments. Unlike the P0 treatment, the values of pH, WHC, and tenderness of the P1-P6 treatments increased, but cooking loss remained the same. In conclusion, the use of the ratio of tapioca flour to porang flour (C5) on beef sausage has better quality than 10:0 (P0).

Effects of Dietary Protein and Lipid Levels on Growth, Metabolism, Antioxidative Capacity, and Fillet Quality of Adult Triploid Rainbow Trout Farmed in Net Cage.

The research is aimed at investigating the effects of dietary protein and lipid levels on adult triploid rainbow trout growth performance, feed utilization, digestive and metabolic enzyme activities, antioxidative capacity, and fillet quality. Nine diets containing three dietary protein levels (DP) (300, 350, and 400 g kg-1) and three dietary lipid levels (DL) (200, 250, and 300 g kg-1) were prepared using a 3 × 3 factorial design. In freshwater cages, 13,500 adult female triploid rainbow trout (3.2 ± 0.1 kg) were cultured for 77 days. Triplicate cages (500 fish per cage) were used as repetitions of each experimental diet. The findings revealed that as DP increased to 400 g kg-1 and DL raised to 300 g kg-1, the weight gain ratio (WGR) elevated significantly (P < 0.05). However, when DP ≥ 350 g kg-1, WGR was similar in the DL250 and DL300 groups. As DP raised to 350 g kg-1, the feed conversion ratio (FCR) notably decreased (P < 0.05). In the DP350DL300 group, lipids had a protein-sparing impact. High DP diet (400 g kg-1) generally improved fish health status by increasing antioxidant capacity in the liver and intestine. A high DL diet (300 g kg-1) showed no harmful effect on hepatic health based on plasma levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and antioxidant capacity in the liver. For fillet quality, a high DP diet could increase fillet yield, improve fillet hardness, springiness, and water-holding capacity values, and inhibit the production of off-flavors caused by n-6 fatty acids. A high DL diet could increase odor intensity, and EPA, DHA, and n-3 fatty acid concentrations decrease the thrombogenicity index value. The maximum fillet redness value was discovered in the DP400DL300 group. Overall, for adult triploid rainbow trout (≥3 kg), the minimum recommended DP and DL according to growth performance were 400 and 250 g kg-1, respectively; DP and DL based on feed utilization were 350 and 200 g kg-1, respectively; DP and DL based on fillet quality were 400 and 300 g kg-1, respectively.

Dietary Fiber from Navel Orange Peel Prepared by Enzymatic and Ultrasound-Assisted Deep Eutectic Solvents: Physicochemical and Prebiotic Properties.

Dietary fiber (DF) was extracted from navel orange peel residue by enzyme (E-DF) and ultrasound-assisted deep eutectic solvent (US-DES-DF), and its physicochemical and prebiotic properties were characterized. Based on Fourier-transform infrared spectroscopy, all DF samples exhibited typical polysaccharide absorption spectra, indicating that DES could separate lignin while leaving the chemical structure of DF unchanged, yielding significantly higher extraction yields (76.69 ± 1.68%) compared to enzymatic methods (67.27 ± 0.13%). Moreover, ultrasound-assisted DES extraction improved the properties of navel orange DFs by significantly increasing the contents of soluble dietary fiber and total dietary fiber (3.29 ± 1.33% and 10.13 ± 0.78%, respectively), as well as a notable improvement in the values of water-holding capacity, oil-holding capacity, and water swelling capacity. US-DES-DF outperformed commercial citrus fiber in stimulating the proliferation of probiotic Bifidobacteria strains in vitro. Overall, ultrasound-assisted DES extraction exhibited potential as an industrial extraction method, and US-DES-DF could serve as a valuable functional food ingredient. These results provide a new perspective on the prebiotic properties of dietary fibers and the preparation process of prebiotics.

Screening of Lactic Acid Bacteria Strains to Improve the Properties of Non-fat Set Yogurt by in situ EPS Production

Some lactic acid bacteria (LAB) are capable of producing exopolysaccharides (EPS), which can be used in the dairy industry to reduce syneresis and improve the viscosity and texture of fermented products. The aim of the present study was to screen the EPS-producing capacity of 123 LAB strains isolated from fermented foods to search for those able to produce EPS with the optimal technological aptitude to be applied in non-fat set yogurt manufacture. They were grown on MRS-sucrose and assigned to ropy or mucoid phenotype depending on the appearance of the colonies. Twenty-five of them were selected and assayed for production of both cell-bound EPS (EPS-b) and EPS released to the medium (EPS-r). Those resulting in the most EPS producers (Levilactobacillus brevis UCLM-Lb47, Leuconostoc mesenteroides subsp. mesenteroides 6F6-12 and Leuconostoc mesenteroides subsp. mesenteroides 2F6-9) were used to manufacture non-fat set yogurts. These yogurts were analyzed for microbiological and physicochemical properties (pH, titratable acidity, total solids), water-holding capacity, apparent viscosity, and sensory characteristics during a 28-day cold storage period. The yogurts made with the selected strains showed higher values of water-holding capacity, EPS concentration, and viscosity in the mouth than the control yogurt, which presented a more fluid texture. The results obtained suggest that the three selected strains could be used to replace hydrocolloids in non-fat set yogurt formulation, obtaining a clean-label product that would improve consumer acceptance.Graphical