Effect of bittern immersion on textural properties and water-holding capacity in beef.

Hard meat has low market value; hence, we used bittern as a novel meat tenderizer for bovine M. semitendinosus, one of a hard muscle. We investigated the effects of beef immersion in bittern, a basic solution primarily comprising MgCl2, on textural properties and water-holding capacity. Muscle samples from M. semitendinosus of Holstein steers were immersed in seven different solutions (RO, NaCl, MgCl2, red wine, pH 3, bittern, and pH 8) and heated at 80°C for 5min. The pH of the beef and immersion solutions, water-holding capacity, and maximum load of the meat were measured. Although beef immersed in red wine (pH 3) had a lower pH and water-holding capacity, that immersed in bittern (pH 8.4) had a higher pH and higher water holding capacity. These results indicate that immersion in acidic red wine may harden beef and that immersion in basic bittern may be more effective in maintaining water-holding capacity and softening beef.

Alterations in the fillet quality of myostatin-knockout red sea bream Pagrus major: Preliminary insights into nutritional, compositional, and textural properties.

Myostatin (MSTN) is a negative regulator of skeletal muscle growth and a popular target for enhancing the productivity of farmed fish. We previously developed an mstn-knockout breed of the aquaculture fish red sea bream (Pagrus major) using genome editing technology. However, little is known about the effects of mstn disruption on the fillet quality of red sea bream and other fish species. In this study, we used fillets of mstn-deficient red sea bream to evaluate their compositional and textural changes during refrigeration. Compared to the wild type, the mutant fillets exhibited an increase in moisture content and a decrease in drippings, indicating an enhanced water-holding capacity. Furthermore, the mutant fillets showed increased water retention and marginally lower collagen content, resulting in lower breaking force, an index of texture. In conclusion, we demonstrated that mstn disruption alters the compositional and textural properties of red sea bream fillets.

Combined Relaxation Spectra for the Prediction of Meat Quality: A Case Study on Broiler Breast Fillets with the Wooden Breast Condition.

This study evaluated the potential of using combined relaxation (CRelax) spectra within time-domain nuclear magnetic resonance (TD-NMR) measurements to predict meat quality. Broiler fillets affected by different severities of the wooden breast (WB) conditions were used as case-study samples because of the broader ranges of meat-quality variations. Partial least squares regression (PLSR) models were established to predict water-holding capacity (WHC) and meat texture, demonstrating superior CRelax capabilities for predicting meat quality. Additionally, a partial least squares discriminant analysis (PLS-DA) model was developed to predict WB severity based on CRelax spectra. The models exhibited high accuracy in distinguishing normal fillets from those affected by the WB condition and demonstrated competitive performance in classifying WB severity. This research contributes innovative insights into advanced spectroscopic techniques for comprehensive meat-quality evaluation, with implications for enhancing precision in meat applications.

Natural aromatic extract of black tea improved the water retention of pork meat batter.

The effect of varying proportions (w/w) of natural aromatic extract of black tea (NAEBT) with pre-emulsification on the water-holding capacity (WHC) of pork meat batter was investigated. The addition of NAEBT significantly reduced the cooking loss (CL) of pork meat batter from 23.95 % to 18.30 % (P < 0.05). Furthermore, NAEBT with pre-emulsification significantly improved the color stability and increased the springiness (P < 0.05). The results of TBARS and carbonyls indicated that NAEBT with pre-emulsification significantly alleviated oxidative damage to proteins (P < 0.05), resulting in an increased level of ß-sheet (P < 0.05), as confirmed by FT-IR analysis. As a result, the water mobility of pork meat batter was restricted (P < 0.05), resulting in an increase in the energy storage modulus (P < 0.05) and a decrease in the pore size. In summary, the WHC of pork meat batter was improved by the antioxidant effect of the NAEBT.

Impact of frozen storage on physicochemical parameters and quality changes in cooked crayfish.

Customers are increasingly opting for ready-to-eat and easy-to-prepare food products, such as cooked crayfish. It is highly valued for its unique taste, tender meat, and nutritional properties. Therefore, we conducted an investigation into its quality parameters over an 8-week period at -20 °C. Parameters such as water distribution, oxidation reactions, color, microstructure, texture properties, and physicochemical parameters were examined. The physicochemical results indicated that as the storage time increased, the levels of pH and TVB-N (total volatile basic nitrogen) showed a significant increase, while the water holding capacity decreased significantly (P < 0.05). After two months of frozen storage, the carbonyl content and TBARS (thiobarbituric acid reactive substances) increased to 4.15 ± 0.16 nmol/mg protein and 1.6 ± 0.00 mg/kg, respectively. Additionally, the total sulfhydryl content decreased to 4.91 ± 0.10 mol/105 g protein, which had an impact on the quality of the crayfish. Electron microscopy revealed that with increasing storage time, the fiber structure gradually deteriorated due to water crystallization, leading to severe damage and breakage of muscle fibers. Interestingly, these changes related to storage affected color and texture parameters, thereby influencing the overall quality of the crayfish.

Use of sustainable packaging materials for fresh beef vacuum packaging application and product assessment using physicochemical means.

Packaging material should guarantee the longest possible shelf life of food and help to maintain its quality. The aim of the study was to assess the physicochemical changes taking place during 28-day ageing of beef steaks packed in two types of multilayer films containing biodegradable polymers - polylactic acid (NAT/PLA) and Mater-Bi® (NAT/MBI). The control group consisted of steaks packed in synthetic polyamide/polyethylene (PA/PE) film. The samples stored in NAT/PLA had significantly lower purge loss than the control samples and the lowest expressible water amount after 14 and 21 days. Following blooming, the most favourable colour was shown in steaks stored in NAT/MBI, with the highest values for the L*, a* and C* parameters and the R630/580 ratio, a high proportion of oxymyoglobin, and the lowest share of metmyoglobin. All steaks, regardless of the type of packaging material, had acceptable tenderness and were stable in terms of lipid oxidation.

The carcass characteristics and quality of meat from lambs grazing perennial wheat with different companion legumes (clover, serradella, lucerne) or a mineral supplement.

This study compared carcasses as well as the quality and mineral concentration of meat from lambs extensively grazing perennial wheat with clover (PW + C), serradella (PW + S), lucerne (PW + L), or a mineral salt supplement (PW + Min). A split-plot design was used, wherein 3 crossbred ewe lambs (n = 72 in total) (sub-plots) grazed each of 4 forage types (plots), that were replicated across 6 locations (blocks). The feeding study concluded after 96 d, when all the lambs were slaughtered. The left longissimus lumborum muscles (LL) were collected and wet aged for either 5 or 56 d post-mortem. Lambs grazing PW + Min were found to produce carcasses with lower dressing percentage values to those grazing the other forage types (P = 0.037). The LL of lambs grazing PW + L had the lowest crude protein values (P = 0.015). Forage type by ageing period interactions did not affect meat quality. The 56 d ageing period resulted in higher purge loss (P < 0.001) and TVB-N values (P < 0.001) and a decline in shear force (P < 0.001) compared to the 5 d ageing period. The other carcass and meat quality parameters were not affected by forage type; including hot carcass weight, pH decline parameters, eye muscle area, cooking loss, intramuscular fat, sarcomere length, colour stability, and concentrations of calcium, iron, magnesium, sodium, and zinc in the LL. These findings confirm that perennial cereal production systems, that include legume forages with contrasting protein, energy, and micronutrient profiles, can deliver comparable lamb carcasses and meat quality.

Effects and mechanism of sub-freezing storage on water holding capacity and tenderness of beef.

In order to explore the effect of sub-freezing storage on water holding capacity and tenderness of beef, four treatments were compared in this study: sub-freezing (-7 °C) fast sub-freezing (-38 °C until the core temperature achieved to -7 °C), superchilling (-1 °C) and fast frozen (-38 °C until the core temperature achieved to -18 °C) with the latter two treatments serving as the controls. The differences in muscle fiber structure, water distribution, protein oxidation and cytoskeletal protein degradation were studied. The results demonstrated that compared with other treatments, the fast sub-freezing treatment resulted in less structural damage to the muscle fibers and had better water holding capacity. Both sub-freezing and fast sub-freezing treatments inhibited protein oxidation compared with superchilling, but the former treatment's level of protein oxidation was higher than that in fast sub-freezing treatment during long-term storage (42 weeks). In addition, the structural proteins in the sub-freezing and fast sub-freezing treatments underwent faster degradation during long-term storage and therefore the meat was more tender compared with the fast frozen treatment. The results indicate that the fast sub-freezing treatment can be potentially applied in beef storage.

An oral gel suitable for swallowing: The effect of micronization on the gel properties and microstructure of κ-carrageenan.

κ-Carrageenan (κ-Car) is an important material for preparing food gels and hydrogels. However, κ-Car gel has issues with high hardness and low water-holding capacity. Modification strategy of micronization is proposed for the first time to explore its influence on texture properties and gelling process of κ-Car gel, and to investigate the feasibility of κ-Car as a food matrix with low strength. κ-Car undergoing 60 min of micronization, the d(0.9) decreased by 79.33 %, SBET and Vtotal increased by 89.23 % and 95.27 %. The swelling rate and degree of gelling process increased significantly, and the microstructure changed from loose large pores to dense small pores resembling a "honeycomb". Importantly, the hardness of gel-60, Milk-60 and PNS-60 decreased by 72.52 %, 49.25 % and 81.37 %. In addition, WHC of gel-60, Milk-60 and PNS-60 was improved. IDDSI tests showed that κ-Car gels, milk gels and PNS gels can be categorized as level 6 (soft and bite-sized), except for PNS-60, which belongs to level 5 (crumbly and moist). Furthermore, the texture and bitter masking effect of milk gels and PNS gels were improved. In conclusion, this study demonstrated that micronization can be a novel approach to improve the gel properties of κ-Car, laying the groundwork for developing dysphagia foods.

Carcass Characteristics and Meat Quality of Wild-Living Mallard (Anas platyrhynchos L.) Originating from Croatia.

The aim of this study was to determine the effects of sex and hunting location on carcass characteristics and meat quality of wild-living mallard (Anas platyrhynchos) from Croatia. Twenty-eight mallards (14 ♂; 14 ♀) were hunted at two hunting locations (HL I = 8 ♂, 8 ♀; HL II = 6 ♂, 6 ♀) in the Croatian lowlands. The carcasses were eviscerated, dressed, and dissected, and the individual internal organs and carcass parts were weighed. The breast muscle (m. pectoralis major) was sampled and used to determine color, pH, drip loss, cooking loss, shear force, and proximate chemical and fatty acid composition. Sex and HL had a significant effect on the majority of carcass characteristics analyzed, but they had no effect on the physical meat parameters. The protein and ash content of mallard meat was significantly higher in HL II (23.16% vs. 22.67%; 1.45% vs. 1.36%, respectively) and the moisture content in females (72.40% vs. 71.59%). HL had a significant effect on SFA (II 33.96% vs. I 29.91%), PUFA n-3 (II 3.55% vs. I 2.69%), PUFA/SFA and n-6/n-3 ratios, and all lipid indices. Females had a significantly higher C22:6n-3 content, a higher PI index and a lower n-6/n-3 ratio. The data presented in this study contribute to a better understanding of game-bird meat quality originating from different regions.

Correlation analysis of phosphorylation of myofibrillar protein and muscle quality of tilapia during storage in ice.

In this study, the correlation between protein phosphorylation and deterioration in the quality of tilapia during storage in ice was examined by assessing changes in texture, water-holding capacity (WHC), and biochemical characteristics of myofibrillar protein throughout 7 days of storage. The hardness significantly decreased from 471.50 to 252.17 g, whereas cooking and drip losses significantly increased from 26.5% to 32.6% and 2.9% to 9.1%, respectively (P < 0.05). Myofibril fragmentation increased, while myofibrillar protein sulfhydryl content and Ca2+-ATPase activity decreased from 119.33 to 89.29 µmol/g prot and 0.85 to 0.46 µmolPi/mg prot/h, respectively (P < 0.05). Correlation analysis revealed that the myofibrillar protein phosphorylation level was positively correlated with hardness and Ca2+-ATPase activity but negatively correlated with WHC. Myofibrillar protein phosphorylation affects muscle contraction by influencing the dissociation of actomyosin, thereby regulating hardness and WHC. This study provides novel insights for the establishment of quality control strategies for tilapia storage based on protein phosphorylation.

Feeding pomegranate pulp to Ghezel lambs for enhanced productivity and meat quality.

Agrifood by-products contain nutrients and bioactive compounds that can be used in the diets of livestock - thereby value-adding to an otherwise waste product of environmental and economic significance. This study investigated the effect of dietary pomegranate pulp in the total mixed ration of Ghezel lambs, evaluating its effect on growth performance, blood parameters, carcass traits, as well as meat quality and shelf life. 3-month-old Ghezel lambs (individually housed, n = 8) were randomly assigned to be either non-supplemented (control) or supplemented with 100 g/kg DM of sun-dried pomegranate pulp for 28 days, post-adjustment. Results showed that supplementation of lamb diets with pomegranate pulp significantly increased liveweight and average daily gains, while not significantly affecting dry matter intake. Lamb serum urea and alkaline phosphatase concentrations and hot carcass weight were increased with pomegranate pulp supplementation. Compared to control lambs, the meat from lambs fed the supplemented diet had higher concentrations of intramuscular fat, mono- and polyunsaturated fatty acid, total unsaturated fatty acid, and meat phenolic compounds. Pomegranate pulp supplemented lambs also had a higher ratio of polyunsaturated to saturated fatty acids; and produced liver tissue with less fat and ash contents. Meat oxidative status (thiobarbituric acid reactive substance) and quality (water holding capacity, colour, and pH) were improved when lambs were supplemented with pomegranate pulp. These findings demonstrate that using pomegranate pulp as a feed for Ghezel lambs has advantageous effects on animal performance and meat quality, offering valorisation of an agrifood by-product.

Soil compaction reversed the effect of arbuscular mycorrhizal fungi on soil hydraulic properties.

Arbuscular mycorrhizal fungi (AMF) typically provide a wide range of nutritional benefits to their host plants, and their role in plant water uptake, although still controversial, is often cited as one of the hallmarks of this symbiosis. Less attention has been dedicated to other effects relating to water dynamics that the presence of AMF in soils may have. Evidence that AMF can affect soil hydraulic properties is only beginning to emerge. In one of our recent experiments with dwarf tomato plants, we serendipitously found that the arbuscular mycorrhizal fungus (Rhizophagus irregularis 'PH5') can slightly but significantly reduce water holding capacity (WHC) of the substrate (a sand-zeolite-soil mixture). This was further investigated in a subsequent experiment, but there we found exactly the opposite effect as mycorrhizal substrate retained more water than did the non-mycorrhizal substrate. Because the same substrate was used and other conditions were mostly comparable in the two experiments, we explain the contrasting results by different substrate compaction, most likely caused by different pot shapes. It seems that in compacted substrates, AMF may have no effect upon or even decrease the substrates' WHC. On the other hand, the AMF hyphae interweaving the pores of less compacted substrates may increase the capillary movement of water throughout such substrates and cause slightly more water to remain in the pores after the free water has drained. We believe that this phenomenon is worthy of mycorrhizologists' attention and merits further investigation as to the role of AMF in soil hydraulic properties.

Effects of ultrasound-assisted dry-curing on water holding capacity and tenderness of reduced­sodium pork by modifying salt-soluble proteins.

This study investigated the effects of ultrasound-assisted dry-curing (UADC) on water holding capacity (WHC) and tenderness of pork at different powers and times, and the mechanism was discussed by considering the functional and structural properties of salt-soluble proteins (SSP). The results showed the application of appropriate UADC treatments (300 W, 60 min) have disruptively affected the muscle structure and decreased the size of the SSP particles (P < 0.05), resulting in the increased concentration of active sulfhydryl and surface hydrophobicity (P < 0.05). These modifications facilitated the dissociation of the myofibrillar structure and the dissolution of more connected proteins, which in turn improved the WHC and tenderness of the pork (P < 0.05). Nevertheless, extended periods of high-power UADC treatments negatively affected the WHC and tenderness of dry-cured pork (P < 0.05). In general, using SSP modified by UADC provides a novel strategy for enhancing the WHC and tenderness of dry-cured products.

Enzymatic Hydrolysis of Salmon Frame Proteins Using a Sequential Batch Operational Strategy: An Improvement in Water-Holding Capacity.

The meat industry uses phosphates to improve the water-holding capacity (WHC) of meat products, although excess phosphates can be harmful to human health. In this sense, protein hydrolysates offer an alternative with scientific evidence of improved WHCs. Salmon frames, a byproduct rich in protein, must be processed for recovery. Enzymatic technology allows these proteins to be extracted from muscle, and the sequential batch strategy significantly increases protein nitrogen extraction. This study focused on evaluating the WHC of protein hydrolysates from salmon frames obtained through double- and triple-sequential batches compared to conventional hydrolysis. Hydrolysis was carried out for 3 h at 55 °C with 13 mAU of subtilisin per gram of salmon frames. The WHC of each hydrolysate was measured as the cooking loss using concentrations that varied from 0 to 5% (w/w) in the meat matrix. Compared with those obtained through conventional hydrolysis, the hydrolysates obtained through the strategy of double- and triple-sequence batches demonstrated a 55% and 51% reduction in cooking loss, respectively, when they were applied from 1% by weight in the meat matrix. It is essential to highlight that all hydrolysates had a significantly lower cooking loss (p ≤ 0.05) than that of the positive control (sodium tripolyphosphate [STPP]) at its maximum allowable limit when applied at a concentration of 5% in the meat matrix. These results suggest that the sequential batch strategy represents a promising alternative for further improving the WHC of hydrolysates compared to conventional hydrolysis. It may serve as a viable substitute for polyphosphates.

Dietary macroalgae Chaetomorpha linum supplementation improves morphology of small intestine and pectoral muscle, growth performance, and meat quality of broilers.

Background and Aim: Over the last decades, the poultry industry has experienced steady growth. Although the industry is gradually expanding in Indonesia, poultry feed production has always been expensive. There is a need to study alternative ingredients to obtain affordable feed from natural resources. Chaetomorpha linum (CL) is an abundant macroalgae available throughout the year in Indonesia. This study aimed to determine the effect of CL on the histological structure of the small intestine, pectoralis muscle, growth performance, and meat quality of broilers. Materials and Methods: This study used 300-day-old chick (DOC) male broilers that were reared until they were 21 days old. This study used a completely randomized design with four treatment groups and five replications, and each replication group contained 15 DOC individuals. The treatment groups consisted of Control (CON), CON basal feed (BF), CL1 (0.75%/kg BF), CL2 (1.5%/kg BF), and CL3 (3%/kg BF) groups. The histological structure of the small intestine, pectoralis muscle, growth performance, and meat quality of the broiler was examined. Results: Small intestine and pectoral muscle histomorphology, growth performance, and meat quality were significantly improved in the CL2 (1.5%) and CL3 (3%) groups compared with the CL1 (0.75%) and CON groups. Conclusion: Dietary CL supplementation ameliorates small intestine and pectoral muscle histomorphology, growth performance, and meat quality of broilers.

Synergistic mechanism of steam blanching and freezing conditions on the texture of frozen yellow peaches based on macroscopic and microscopic properties.

Freezing and blanching are essential processing steps in the production of frozen yellow peaches, inevitably leading to texture softening of the fruit. In this study, the synergistic mechanism of stem blanching, freezing conditions (-20°C, -40°C, -80°C, and liquid nitrogen [-173°C]), and sample sizes (cubes, slices, and half peaches) on macroscopic properties of texture, cellular structure, and ice crystal size distribution of frozen yellow peaches were measured. Blanching enhanced the heat and mass transfer rates in the subsequent freezing process. For nonblanched samples, cell membrane integrity was lost at any freezing rate, causing a significant reduction in textural quality. Slow freezing further exacerbated the texture softening, while the ultra-rapid freezing caused structural rupture. For blanched samples, the half peaches softened the most. The water holding capacity and fracture stress were not significantly affected by changes in freezing rate, although the ice crystal size distribution was more susceptible to the freezing rate. Peach cubes that had undergone blanching and rapid freezing (-80°C) experienced 4% less drip loss than nonblanched samples. However, blanching softened yellow peaches more than any freezing conditions. The implementation of uniform and shorter duration blanching, along with rapid freezing, has been proven to be more effective in preserving the texture of frozen yellow peaches. Optimization of the blanching process may be more important than increasing the freezing rate to improve the textural quality of frozen yellow peaches.

Assessment of energy cane bagasse-derived cellulosic microfiber hydrogels on the growth of potted chili peppers.

Energy cane (Saccharum spp.) bagasse, a type of biomass waste, is often underutilized, burned, or left to dispose of itself. This research aimed to evaluate the potential of converting this bagasse into high-value cellulosic microfiber hydrogels (CMH) for water conservation and potted chili (Capsicum annuum) plant growth. CMH offers a biodegradable alternative to synthetic polyacrylamide (PA) hydrogels and provides the dual benefit of improved water use efficiency and reduced environmental impact due to their ability to naturally break down in the soil. In this study, CMH and PA hydrogels were compared for water retention value (WRV), and reswelling kinetics (RK), as well as their effects on plant height, leaf count, root-to-shoot ratios (R:S ratio), and soil moisture retention. Two versions of CMH, CMH65 and CMH60, were prepared with varying cellulose-chitosan ratios: 65:35 and 60:40, respectively. The hydrogels were tested at four concentrations (0, 0.5, 1.0, and 2.0% w/w) by being mixed in Promix® soil. Observations were recorded over a 16-day period without additional water. Also, the WRV of hydrogels at 240 min and RK (10-180 min) were compared over three swelling-deswelling cycles. The PA hydrogel exhibited higher WRV (exceeding 450%) compared to CMH (45%). However, PA led to reduced plant height, leaf count, and R:S ratio when compared to higher concentrations of CMH65 and CMH60. In general, CMH60 (0.5% and 2%) exhibited superior plant growth. All hydrogels exhibited a significant decrease (p < 0.05) in WRV across successive cycles. Notably, during cycle 2, both CMH65 and CMH60 peaked in WRV at 10 and 20 min, respectively, compared to cycle 1. This study demonstrates the potential of bagasse-derived hydrogels as a value-added product for water conservation and crop growth.

Enhancing the Quality of Low-Salt Silver Carp (Hypophthalmichthys molitrix) Surimi Gel Using Psyllium Husk Powder: An Orthogonal Experimental Approach.

Low-salt surimi production is crucial as it addresses health concerns related to sodium intake while maintaining the quality and shelf-life of seafood products. This research focused on optimizing the gelation conditions for silver carp surimi with the addition of psyllium husk powder at low salt concentrations (0.5% and 1%, w/w) to investigate the effects of psyllium husk powder concentration, temperature, and time on gel strength and water-holding capacity. The quality was assessed in terms of gel strength and water-holding capacity. Following a single-factor exploration, a three-level orthogonal experiment was designed to evaluate the influence of these three variables using a combined scoring system. Results indicated that psyllium husk powder levels between 0.1% and 0.3% (w/w) enhanced gel strength and water-holding capacity. The optimal conditions were identified as follows: 1% (w/w) NaCl with 0.2% (w/w) psyllium husk powder for 2.5 h at 35 °C, and 0.5% (w/w) NaCl with 0.3% (w/w) psyllium husk powder for 3 h at 35 °C. Texture profile analysis revealed that psyllium husk powder increased the hardness of the surimi gel, promoting myosin cross-linking and denser gel structure. Compared to traditional surimi gel, which relies on ionic bonds, the optimized gel showed higher levels of disulfide cross-linking and enhanced hydrophobic interactions, resulting in a stronger gel structure. Sensory evaluation suggested that surimi gels with psyllium husk powder were perceived as better than those without psyllium husk powder. The study concludes that selecting the appropriate psyllium husk powder quantity and thermal processing conditions based on salt concentration can significantly improve the quality of low-salt surimi gels. Error analysis using one-way ANOVA was performed on all experimental data and (p < 0.05) indicated the significant difference.

Immunoregulatory and antioxidant properties of tryptophan in quail chick.

A dose-response assay was carried out to investigate the effects of graded levels of dietary tryptophan (Trp) on blood variables, immunity, and meat quality in quail chicks during the last two weeks of the growing period. A total of 420 21-day-old quail chicks were randomly distributed across the seven experimental groups (i.e., 2.12, 2.25, 2.38, 2.51, 2.64, 2.77, and 2.90 g Trp/kg of diet) with four pen replicates of 15 birds each. Blood variables, including uric acid (UA), albumin (ALB), and triglycerides (TG), responded inversely to increasing dietary Trp (P < 0.001). The concentration of aspartate aminotransferase (AST) in serum, the relative weight of bursa of Fabricius (BF), immunoglobulin G (IgG), water holding capacity (WHC), and antigen production against the sheep red blood cells (SRBC) increased with increasing dietary Trp (P < 0.001). In contrast, the concentration of malondialdehyde (MDA) and drip loss in meat samples decreased with increasing dietary Trp (P < 0.001). The best models for optimal dietary Trp were identified based on a statistical merit basis known as the model accuracy index (δ). The estimated dietary Trp for optimizing ALP, UA, total protein (TP), TG, SRBC, IgG, BF, drip loss, WHC, and MDA were obtained at 2.347, 2.371, 2,372, 2.485, 2,691, 2.738, 2.306, 2.359, 2.247, and 2.500 g/kg of diet, respectively. Principal component analysis showed that UA, TG, IgG, and drip loss had a higher association with dietary Trp rather than other responses. Considering the high δ and eigenvalues of the models, the best estimation of dietary Trp level required for the optimization of the studied traits in quail chicks would be 2.738 g Trp/kg of diet, which was significantly higher than that recommended for the quail performance by NRC (1994).