Meat Protein Research Articles

Probiotics effects on the growth performance and meat quality of broiler chickens

Context In the limited field of research on Kazakhstan’s poultry, this study explores a new area by investigating the lack of studies on the impact of probiotics from camel milk and mare’s milk. This study provides valuable knowledge about an important aspect of poultry production in the region. Aims The purpose of the study was to investigate the effect of probiotics isolated from traditional fermented dairy products, fermented camel milk (shubat) and fermented mare’s milk (koumiss) on the growth performance and meat quality of broiler chickens. Methods In total, 240 1-day-old Ross 308 chicks were randomly separated into four treatment groups of three replicates (20 birds per replicate). Three experimental groups were fed by basal diet plus drinking water containing 0.25 mL, 0.5 mL, and 1.0 mL of probiotics per bird (Pro1, Pro2, and Pro3 respectively). The control group was fed by basal diet plus drinking water. The carcass characteristics included the weights of the body and carcass rate. Organoleptic analysis, proximate composition, pH, drip loss, cook loss and were used to determine meat-quality properties. Key results According to the study results isolated probiotics Lacticaseibacillus paracasei subsp. paracasei SH1, Enterococcus faecalis SH6, and Kazachstania unispora Y 2.2 had a significant effect on body and carcass weight (P < 0.05). Average daily gain and feed conversion ratio were also improved in probiotics groups (P < 0.05). Additionally, Pro 2 group had increased meat protein contents (P < 0.05). No significant differences in organoleptic quality between the control and experimental groups fed with the probiotics were determined. Conclusions Traditional fermented dairy products could become a source of new effective probiotics useful to improve broiler production. Implications The readily available shubat and koumiss in Kazakhstan present a promising opportunity for establishing localised probiotic production for poultry, indicating a viable path for promoting sustainable and tailored approaches to poultry farming in the region.

Comprehensive research on the properties of advanced glycation end products in food and biological samples and their harmful role in inducing metabolic diseases.

Advanced glycation end products (AGEs) are formed by the Maillard reaction, a nonenzymatic process that occurs widely in cooking, food processing, and within the human body. Primarily, AGEs are formed by the glycation of reducing sugars with amino groups, and this process is heat-dependent. With changes in lifestyle, there has been an increase in the diversity of dietary habits, including those patterns associated with Western diets, which include the consumption of processed foods that are rich in AGEs. Excessive intake and exposure to AGEs are known to cause abnormalities in body function such as obesity, diabetes, and fatty liver, and the beneficial effects of AGEs in food processing in improving food flavor and quality. To obtain meaningful data regarding AGEs in a variety of food and human samples, it is necessary to more precisely characterize and analyze the AGEs extracted from samples to obtain accurate results. This review explores the recent analytical research and characterization of AGEs in foods, including casein, β-lactoglobulin, soy protein, and meat protein, and in human samples, such as glycated-albumin, hemoglobin, and plasma. Additionally, it explores the metabolic fate of AGEs in the body and the mechanisms of disease associated with metabolic abnormalities that may be caused by the consumption of foods containing AGEs. This review aims to provide an overview of the perspectives of relevant recent and future research on metabolic abnormalities caused by foods containing AGEs or by AGEs produced in the body.

Effects of Bergamot (Citrus bergamia Risso) By-Product on Growth Performance and Meat Quality of Growing Rabbits.

This study aimed to investigate the effects of feeding dried bergamot pulp to rabbits on animal performance and meat quality. Thirty rabbits were assigned to two groups (balanced for body weight, 804.4 ± 2.35 g) and fed individually for 60 days a basal diet (control) or the basal diet in which part of the cereals was replaced with 10% of dried bergamot pulp (DBP). There were no effects of DBP on growth performance, carcass yield, or the crude protein and ether extract composition of meat. The concentrations of α-linolenic acid (C18:3 n-3) and eicosapentaenoic acid (C20:5 n-3) increased in the longissimus thoracis et lumborum muscle (p < 0.01 and p = 0.021, respectively) after integrating dried bergamot pulp into the diet, leading to higher levels of total of ω-3 fatty acids (p < 0.01) compared to the control treatment. The inclusion of dried bergamot pulp improved the oxidative stability in meat (p < 0.001), where TBARS values were lower after 4 and 7 days of refrigerated storage (p < 0.001) in the DBP group than in the control group. Finally, feeding dried bergamot pulp to rabbits improves meat quality without negatively influencing growth performance.

Canadians' experiences of alternative protein foods and their intentions to alter current dietary patterns

Despite established evidence about the environmental and health benefits of alternative protein foods (APF), considerable knowledge gaps and misconceptions remain toward APF. Drawing on a national survey (1800+ responses), the study explores Canadians' experiences of APF and intentions to alter current dietary patterns focusing on four APF – plant-based alternative proteins (PBAP) – plant-based (PB) milk, PB meat, lab-grown (LG) meat, and other alternative proteins (OAP) – and two animal-based foods (ANBF)– milk and meat. Data were collected based on a proportional stratified sampling method from all regions of Canada and analyzed using econometric models. While PB milk was the most consumed APF, followed by PB meat, LG meat was the least tried among participants. Perceived complexity of APF discouraged individuals from cutting back on ANBF, while increasing the consumption of APF. Perceived relative advantage was positively related to the adoption of APF. Perceived compatibility strongly influenced individuals’ adoption of PB meat and OAP. Likewise, perceived trialability significantly influenced the adoption of PB milk and PB meat. Despite the perception that APF may have high health related risks associated with processing, additives, calorie and sugar content, this did not prevent individuals from consuming PB milk and OAP. However, perceived risks did affect intentions to alter dietary patterns in the next 12 months. Additionally, meat attachment and sustainability orientation significantly predicted current consumption decisions of APF and intentions to alter dietary patterns. Although sustainability orientation motivates dietary changes, it did not always lead to extreme shifts. Finally, several demographic variables (age, gender, and education), dietary preferences (being omnivore), and residential area and region had influence on current consumption decisions and future intentions. In conclusion, by controlling several factors and through a comparative analysis of various protein sources, the study offers insights into the interplay of innovation-adoption characteristics, perceived risks, meat attachment and sustainability orientation in understanding dietary choices and provides some implications for industry stakeholders and policies promoting APF.

Effect of ultrasound and marination on functional and sensory properties, protein profiles and bioaccessibility of amino acids in turkey meat

SummaryThis study investigates the impact of ultrasound treatment and marination on turkey meat proteins, focusing on functional and sensory properties and protein hydrolysis. Three different treatments, marination (M), ultrasound (US) and a combination of ultrasound and marination (USM), were applied to turkey meat. The USM caused the highest water‐holding capacity, increased tenderness and improved the general acceptability of turkey meat. SEM images of raw samples showed that US and M changed the structure of muscle fibres, exhibiting more cavities and irregular, broken and separated fibres. Cooking changed the muscle fibres of the sample, forming several cavities and separate fibres. SDS‐PAGE profiles showed that different treatments affected protein solubility during gastric digestion. Ultrasound treatment caused the loss of some essential amino acids in the supernatant of intestinal digests, including lysine, leucine and tyrosine. In vitro bioaccessibility of leucine, threonine, lysine, valine and isoleucine was the highest in the untreated sample.

Chlorella vulgaris as a Nutraceutical Source for Broilers: Improving Meat Quality and Storage Oxidative Status.

This study aimed to assess the impact of Chlorella vulgaris supplementation in broilers' diet, alone or in combination with vitamin E, on meat quality parameters, nutritional value, and oxidative stability during storage time. An experiment was conducted on 180 COBB 500 broiler chickens (14 days old), assigned into six treatments, following a 2 × 3 factorial arrangement. A corn-soybean meal diet was supplemented with three levels of C. vulgaris (0% in group C1, 1% in E1, 2% in E2), two levels of vitamin E (0% in C1, 250 ppm in C2), and a combination of them (1% C. vulgaris + 250 ppm vitamin (E3), 2% C. vulgaris + 250 ppm vitamin (E4)). Dietary incorporation of C. vulgaris, including those supplemented with vitamin E, resulted in a significant increase in meat protein content. DPA and DHA levels increased by 2.01-fold and 1.60-fold in the 2% C. vulgaris + vitamin E group. The PUFA/SFA ratio was increased across all dietary treatments (p < 0.0001). HPI and h/H registered the highest values as a result of 2% C. vulgaris supplementation, being linked with a positive effect in lowering cholesterol levels. Supplementation with 2% C. vulgaris and vitamin E exhibited a 1.45-fold increase in vitamin E concentration in thigh meat compared to the control group, being the highest level registered in thigh meat in this experiment. Metmyoglobin concentrations registered lower values in the thigh meat of the experimental groups, while deoxymyoglobin increased in the same groups when compared to the control group. The inclusion of C. vulgaris (1% and 2%) in combination with vitamin E (250 mg/kg) in broiler diets exhibited the best prevention of lipid oxidation after 7 days of refrigerated storage, defined by the highest efficiency factors assessed in terms of secondary oxidation products.

A meta-analysis of the meat physicochemical parameters of broiler chickens fed insect-based diet.

A total of 23 studies were identified in a literature search performed in the Scopus, Science Direct and Google Scholar databases for meta-analysis. The criteria used include studies that were published from 2015 to 2023 and those reporting the effects of insect meal utilisation in poultry diets. Data on live weight (LW), carcass weight (CW), moisture, meat pH, lightness (L*), redness (a*), yellowness (b*), proximate composition (protein, fat and ash content) and shear force in broilers were subjected to OpenMEE software, and data were pooled using a random-effect model. Subgroup analysis and meta-regression were performed to ascertain the influence of dietary insect meals on the response of meat aspects and the source of heterogeneity, respectively, using the following moderators (insect species, dosage level, feeding duration and age at slaughter). The results indicated that dietary insect meal did not affect LW, CW, meat L*, pH, shear force, moisture, fat and ash content. In contrast, dietary insect meal increased the a* of the meat (standardised mean differences (SMDs) = 1.03; 95% confidence intervals (CIs) = 0.484-1.578; p ≤ 0.001), b* (SMD = 1.117; 95% CI = 0.334-1.90; p = 0.005), and meat protein content (SMD = 0.365; 95% CI = 0.031-0.7; p = 0.032). The subgroup analysis showed that insect meal dosage of ≤10% and age at slaughtered ≤35 days had improved the LW, CW and meat L*. In addition, the meat a*, protein and ash content were also influenced by insect species, dosage levels and age at slaughter. In conclusion, ≤10% of either Hermetia illucens or Tenebrio molitor can be included in broiler diets without compromising the LW, CW, meat pH, colour, shear force, moisture, fat and ash content in broilers. The study therefore indicated that insect meals have a bright future as an alternative protein source in poultry diets.

Effects of ultrasound-assisted marination on spent hen meats: Microstructure, textural and technological properties

The purpose of this study was to investigate the effects of ultrasound-assisted marination in distilled water, kiwi, and lemon juices on the water holding capacity, pH, color (L*, a*, b*), cooking loss, and textural and sensory qualities of spent hen breast meat. In addition, differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) images of the meats were determined. When compared to the marination method used alone, the water-holding capacity and drip loss of the spent hen meat samples increased as a result of ultrasound-assisted marination (P < 0.05). When compared to the other samples, the group marinated in lemon juice with ultrasonic assistance had a lower cooking loss value (P < 0.01). The results showed that the samples marinated in lemon juice had the highest L* and b* values, however, the samples marinated in lemon juice with and without ultrasound assistance had the lowest a* values. In terms of textural characteristics, the sonication treatment further reduced the shear force, even if the marination with the lemon and kiwi juices only slightly reduced it as compared to the control. The samples marinated in lemon juice with sonication support exhibited the lowest hardness value. According to DSC, the ultrasound-assisted marination process decreased the thermal denaturation temperatures of meat proteins. In terms of the SEM analysis results, it was observed that the inter-myofibrillar spaces were more evident in the chicken breast meats that underwent ultrasound-assisted marination compared to the only marination groups.

Perceptions of three diets varying in animal- and plant-based protein contents: Analysis of participant experience diaries

The market for new plant protein-based meat substitutes is expanding, although their consumption remains limited compared to animal-based protein sources. Further research is necessary to comprehend the perceptions of diets in which animal-based protein sources are partially replaced with plant proteins. This qualitative study is part of an intervention trial, during which participants adhered to one of the three intervention diets for 12 weeks: the ANIMAL diet (70% animal-based protein/30% plant-based protein), the 50/50 diet (50% animal/50% plant) or the PLANT diet (30% animal/70% plant).The dataset comprises 79 experience diaries from healthy participants aged 23 to 69. The study investigated perceptions of intervention diets, the meat protein (MPPs) and the plant protein products (PPPs) included in the intervention and self-reported changes in perceptions during the intervention period. These perceptions were categorized into eight themes: body-related experiences, practicalities and everyday life, sensory properties, social situations and special occasions, familiarity and novelty, health, ethical aspects, and non-specific liking. Across the diets, body-related experiences were the most frequently mentioned theme. The ANIMAL diet received more negative than positive comments. In contrast, comments on the 50/50 diet were relatively balanced between positive and negative, and the PLANT diet received more positive comments than negative ones. The PPPs were commented on in a positive way more often than the MPPs were. With consistent exposure, participants reported more positive than negative changes in perceptions. However, there is still room for improvement in enhancing the sensory quality and ease of food preparation of PPPs.

Substitution of One Meat-Based Meal With Vegetarian and Vegan Alternatives Generates Lower Ammonia and Alters Metabolites in Cirrhosis: A Randomized Clinical Trial.

Diet can affect ammoniagenesis in cirrhosis and hepatic encephalopathy (HE), but the impact of dietary preferences on metabolomics in cirrhosis is unclear. As most Western populations follow meat-based diets, we aimed to determine the impact of substituting a single meat-based meal with an equal protein-containing vegan/vegetarian alternative on ammonia and metabolomics in outpatients with cirrhosis on a meat-based diet. Outpatients with cirrhosis with and without prior HE on a stable Western meat-based diet were randomized 1:1:1 into 3 groups. Patients were given a burger with 20 g protein of meat, vegan, or vegetarian. Blood for metabolomics via liquid chromatography-mass spectrometry and ammonia was drawn at baseline and hourly for 3 hours after meal while patients under observation. Stool microbiome characteristics, changes in ammonia, and metabolomics were compared between/within groups. Stool microbiome composition was similar at baseline. Serum ammonia increased from baseline in the meat group but not the vegetarian or vegan group. Metabolites of branched chain and acylcarnitines decreased in the meat group compared with the non-meat groups. Alterations in lipid profile (higher sphingomyelins and lower lysophospholipids) were noted in the meat group when compared with the vegan and vegetarian groups. Substitution of a single meat-based meal with a non-meat alternatives results in lower ammoniagenesis and altered serum metabolomics centered on branched-chain amino acids, acylcarnitines, lysophospholipids, and sphingomyelins in patients with cirrhosis regardless of HE or stool microbiome. Intermittent meat substitution with vegan or vegetarian alternatives could be helpful in reducing ammonia generation in cirrhosis.

Discovery of a temperature-dependent protease spoiling meat from Pseudomonas fragi: Target to myofibrillar and sarcoplasmic proteins rather than collagen

Chilled meat frequently suffered microbial spoilage because bacteria can secrete various proteases that break down the proteins. In this study, Pseudomonas fragi NMC 206 exhibited a temperature-dependent secretion pattern, with the ability to release the specific protease only below 25 °C. It was identified as alkaline protease AprA by LC-MS/MS, with the molecular weight of 50.4 kDa, belonging to the Serralysin family metalloprotease. Its significant potential for meat spoilage in situ resulted in alterations in meat color and sensory evaluation, as well as elevated pH, total volatile basic nitrogen (TVB-N) and the formation of volatile organic compounds (VOCs). The hydrolysis of meat proteins in vitro showed that AprA possessed a considerable proteolysis activity and degradation preferences on meat proteins, especially its ability to degrade myofibrillar and sarcoplasmic proteins, rather than collagen. These observations demonstrated temperatures regulated the secretion of AprA, which was closely related to chilled chicken spoilage caused by bacteria. These will provide a new basis for the preservation of meat products at low temperatures.

Study of the effect of a combination of biocoordination compounds and a water-based probiotic on the performance of broiler chickens

The aim of the study was to investigate the effect of a combined probiotic, which included microbial mass of a mixture of live bacteria L. acidophilum, B. adolescentis and chelate complex of amino acids with chromium on the dynamics of growth performance, feed intake and digestibility, slaughter quality, morphological and biochemical blood parameters in the organism of broiler chickens of Arbor Aikress cross (CJSC «Poultry Farm Orenburgskaya»). Up to two weeks of age, the birds were in the preparatory period and received the basic diet (n=60). Starting from the age of 15 days, broilers of the experimental group additionally received with water a combined probiotic at a dose of 0,2 g/kg, and with feed a chelate complex of amino acids with chromium at a dose of 200 mg/kg. The duration of the study period was 28 days. The body weight of broiler chickens of the experimental group was statistically significantly higher by 28 and 42 days of age than in the control by 18 % (p=0,03) and 14 % (p=0,01), respectively. The weight of gutted carcass in the experimental group was higher than in the control group by 24 % (p=0,05). Addition of the studied additive to the diet of birds contributed to the reduction of feed costs per 1 kg of gain by 0,3 kg (14 %). Digestibility of crude protein in the experimental group was significantly higher by 2,7 % (p=0,03). The level of protein in meat of the experimental group was higher than in the control by 2,76 % (p=0,03). The introduction of probiotic in the diet had a stimulating effect on antioxidant enzymes. In broiler chickens of the experimental group the activity of superoxide dismutase and glutathioperoxidase in blood serum was significantly higher than in the control by 13 % (p=0,02) and 7,5 % (p=0,03), respectively. Thus, probiotics, together with the complex of amino acids with chrome, due to its multipurpose action can have a positive effect on the organism of farm poultry and increase the efficiency of poultry farming.

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.

Hybrid meat batter system: effects of plant proteins (pea, brown rice, faba bean) and concentrations (3–12%) on texture, microstructure, rheology, water binding, and color

A lean meat batter system was mixed with four plant proteins at 3, 6, 9, and 12% (w/w): pea protein A (PA), pea protein B (PB), brown rice protein (BR) and faba bean protein (FB). Texture profile analysis (TPA) revealed that increasing plant protein levels hardened the hybrid meat batters, with PA and PB leading to the hardest gels. TPA results were supported by micrographs, demonstrating that the two pea proteins formed large aggregates, contributing to a firmer hybrid meat gel. Dynamic rheology showed that the incorporation of plant proteins lowered the storage modulus (G') during the heating stage (20 to 72°C), yet the 6% PA treatment produced a final G' (after cooling) closest to the control (CL). Nuclear Magnetic Resonance (NMR) T2 relaxometry also demonstrated that plant proteins reduced the water mobility in hybrid meat batters. Results were in line with the cooking loss, except for a higher cooking loss in the BR formulation compared to the CL. Color measurement showed that increasing plant protein levels led to darker and yellower meat batters; however, the effect on redness varied among treatments. Overall, the findings suggest that pea proteins have superior functionality and compatibility within a lean poultry meat protein system, compared to BR and FB tested here.

Acetylation and Phosphorylation Regulate the Role of Pyruvate Kinase as a Glycolytic Enzyme or a Protein Kinase in Lamb.

Protein post-translational modifications (PTMs) play an essential role in meat quality development. However, the effect of specific PTM sites on meat proteins has not been investigated yet. The characteristics of pyruvate kinase M (PKM) were found to exhibit a close correlation with final meat quality, and thus, serine 99 (S99) and lysine 137 (K137) in PKM were mutated to study their effect on PKM function. The structural and functional properties of five lamb PKM variants, including wild-type PKM (wtPKM), PKM_S99D (S99 phosphorylation), PKM_S99A (PKM S99 dephosphorylation), PKM_K137Q (PKM K137 acetylation), and PKM_K137R (PKM K137 deacetylation), were evaluated. The results showed that the secondary structure, tertiary structure, and polymer formation were affected among different PKM variants. In addition, the glycolytic activity of PKM_K137Q was decreased because of its weakened binding with phosphoenolpyruvate. In the PKM_K137R variant, the actin phosphorylation level exhibited a decrease, suggesting a low kinase activity of PKM_K137R. The results of molecular simulation showed a 42% reduction in the interface area between PKM_K137R and actin, in contrast to wtPKM and actin. These findings are significant for revealing the mechanism of how PTMs regulate PKM function and provide a theoretical foundation for the development of precise meat quality preservation technology.

Comparative study of a liposome and emulsion system with cinnamon essential oil on the quality and proteolysis of refrigerated minced pork.

Essential oils have been recognized for their strong antibacterial property, making them an innovative approach for preserving meat. However, their chemical instability and direct impact on meat proteins limit their application. To overcome these limitations, various loading systems have been explored. This study aimed to compare the effect of cinnamon essential oil (CEO) loaded in a liposome and emulsion system on the proteolysis of minced pork and to evaluate the advantages of each delivery system in preventing microorganism-induced quality deterioration of meat. Minced pork treated with CEO-liposomes exhibited lower pH, total volatile basic nitrogen (TVB-N), and total viable count (TVC) values than CEO-emulsions and provided better protection against microorganisms. SDS-polyacrylamide gel electrophoresis (PAGE) analysis confirmed that CEO-liposome was more effective in protecting proteins from degradation. Moreover, CEO-liposome produced lower amount of bitter amino acids and harmful biogenic amines. Antibacterial mechanisms indicated that CEO-liposome exhibited a stronger inhibitory effect against major spoilage bacteria in meat products by increasing cell membrane permeability. The membrane damage was further supported by an increase in conductivity and the leakage of nucleic acids. Compared to the CEO-emulsion system, CEO-liposome emerged as an effective preservative for minced pork. These results provided important theoretical support for using a bioactive compound delivery system to prevent microorganism-induced quality deterioration in meat.

Detection and quantification of 4-oxo-2-nonenal in plant-based meat and beef

Oxidative degradation of lipids and proteins in food causes loss of nutrition, produces genotoxic oxidative byproducts, and increases health concerns. 4-Oxo-2-nonenal (4-ONE) is a highly reactive and toxic aldehyde, recently identified as a novel lipid peroxidation byproduct. However, naturally formed 4-ONE and its interaction with proteins in food are still not fully understood. In this study, methods for the detection and quantification of 4-ONE were further developed and used. The developed method successfully detected the formed lipid oxidation products (LOPs) and protein oxidation products (POPs) during cooking, as well as after in-vitro digestion of plant-based (PB) meat and beef. The method used exhibited consistencies of detection of 4-ONE in raw, cooked, and in-vitro digested PB meat and beef samples. Furthermore, the findings of this study show that PB meat had significantly higher levels of POPs but lower levels of aldehydes (4-ONE and malondialdehyde) than beef samples. The results revealed the LC–MS/MS method for detecting and quantifying 4-ONE as a novel lipid oxidation marker was promising. Furthermore, the results indicated that the protein in PB meat may be prone to covalent modification of aldehyde and free radical attacks, thus reducing its proteolysis during digestion. Future studies should further assess the covalent binding ability of aldehydes (especially 4-ONE) in different types of protein, as well as the interaction between lipid and protein oxidation. Processors should develop new strategies to avoid undesirable LOPs and POPs in PB meat and beef, to improve their nutrition and relieve long-term health concerns.

Effects of Frying, Freezing, Boiling, and Thawing Processes on Proximate, PH and Energy Values of Fresh (Oncorhynchus mykiss)

Objective/Background: Oncorhynchus mykiss is the most popular type of freshwater fish consumed by Iranians. It has delicious taste and high nutritional value. The purpose of processing and preserving fish is to get it to the end consumer in a good, usable condition. Methods: This study is a descriptive study that compares and determines the analysis results of proximate, protein, and fat between fresh and processed fish using the standard method of AOAC and compares the analysis of this study with that of other studies. The effect of the processing methods’ nutritional composition is determined. In addition to fresh fish, 5 treatments are used for the 5 different methods of fish processing. Results: The fresh fish and the different processed samples were analyzed by standard AOAC methods, and their pH was measured. After analyzing the macronutrient compounds of different samples, the energy values were then calculated in kcal. The moisture content ranged from 72.50% for fresh fish to 19.50% for frozen fish, while the fat content ranged from 8.09% for fresh fish to 64.47% for frozen fish. The ash contents were found to range from 4.82% to 5.82%, while the protein contents were found to range from 10.47% to 13.59%. The results showed that quick freezing of fish preserved nutrients with a high percentage of energy. This sample was recommended for consumption, followed by samples thawed in oven and in hot water. The fried and boiled samples were in the next stages of quality and energy values. Conclusions: Because the fat content of this type of fresh fish is high, and if fish feed and its nutrition are protein materials with high biological value, it will be useful to increase the percentage of meat protein for it to grow.

Comparing motivations and barriers to reduce meat and adopt protein alternatives amongst meat-eaters in Australia, China and the UK

Motivations are central in determining consumer food choices and provide insights regarding barriers to change. Given the global need to transition towards more sustainable protein consumption patterns, understanding cross-cultural motivations is important. The present research aimed to address this knowledge gap by reviewing motivations to reduce meat and to adopt meat substitutes, edible insects and cultured meat amongst meat-eating consumers in Australia, China and the UK (n = 1,777). An online survey captured the importance of key motivations via closed-ended statements, with barriers to change collected via open-ended questions for extremely unwilling consumers. Results found food safety and environmental benefits to be the most important motives for meat reduction and protein alternatives adoption. Chinese and UK consumers were more motivated by these factors compared to Australian consumers who had the greatest proportion of consumers unwilling to reduce based on the belief meat consumption is necessary for health reasons. Relative differences in motivational importance were also apparent by protein alternative type. In general, the greatest proportion of unwilling responses amongst Australians (n = 245) related to the use of meat substitutes, whilst for Chinese (n = 160) and UK consumers (n = 97) it related to edible insects. Six key themes were identified amongst extremely unwilling consumers, with the protein alternatives being perceived as; Unhealthy, Unnecessary, Unsustainable, Unsafe, Unnatural and Unappealing. The prominence of themes differed between countries and across protein categories, but the perception that alternatives were unnecessary was a communal theme. Overall, the findings provide interesting insights and recommendations to support country-specific protein transitions.

The Cryoprotective Effect of an Antifreeze Collagen Peptide Complex Obtained by Enzymatic Glycosylation on Tilapia.

Antifreeze peptides have become effective antifreeze agents for frozen products, but their low quantity of active ingredients and high cost limit large-scale application. This study used the glycosylation of fish collagen peptides with glucosamine hydrochloride catalyzed by transglutaminase to obtain a transglutaminase-catalyzed glycosylation product (TGP) and investigate its antifreeze effect on tilapia. Compared with the blank group, the freshness (pH value of 6.31, TVB-N value of 21.7 mg/100 g, whiteness of 46.28), textural properties (especially hardness and elasticity), and rheological properties of the TGP groups were significantly improved. In addition, the protein structures of the samples were investigated using UV absorption and fluorescence spectroscopy. The results showed that the tertiary structure of the TGP groups changed to form a dense polymer. Therefore, this approach can reduce the denaturation and decomposition of muscle fibers and proteins in fish meat more effectively and has a better protective effect on muscle structure and protein aggregation, improving the stability of fish meat. This study reveals an innovative method for generating antifreeze peptides by enzymatic glycosylation, and glycosylated fish collagen peptide products can be used as new and effective green antifreeze agents in frozen foods.