Effect of citric acid on physicochemical properties and protein structure of low-salt restructured tilapia (Oreochromis mossambicus) meat products

Diversified Techniques for Restructuring Meat Protein-Derived Products and Analogues

Accompanied by the rapid growth of the global population and increasing public awareness of protein-rich foods, the market demand for protein-derived products is booming. Utilizing available technologies to make full use of meat by-products, such as scraps, trimmings, etc., to produce restructured meat products and explore emerging proteins to produce meat analogues can be conducive to alleviating the pressure on supply ends of the market. The present review summarizes diversified techniques (such as high-pressure processing, ultrasonic treatment, edible polysaccharides modification, enzymatic restructuring, etc.) that have been involved in restructuring meat protein-derived products as well as preparing meat analogues identified so far and classifying them into three main categories (physical, chemical and enzymatic). The target systems, processing conditions, effects, advantages, etc., of the included techniques, are comprehensively and systemically summarized and discussed, and their existing problems or developing trends are also briefly prospected. It can be concluded that a better quality of restructured products can be obtained by the combination of different restructuring technologies. This review provides a valuable reference both for the research and industrial production of restructured meat protein-derived products and analogues.

pH-regulated Tannic acid and soybean protein isolate adhesive for enhanced performance in plant-based meat analogues

A food adhesive comprising tannic acid (TA) and soybean protein isolate (SPI) was developed to establish a cohesive bond between soy protein gel and simulated fat. The impact of varying TA concentrations and pH levels on the adhesive's rheology, thermal stability, chemical structure, and tensile strength were investigated. Rheological results revealed a gradual decrease in adhesive viscosity with increasing TA content. Differential scanning calorimetry (DSC) and thermal gravimetric (TG) results indicated that the stability of the adhesive improved with higher TA concentrations, reaching its peak at 0.50% TA addition. The incorporation of TA resulted in the cross-linking of amino group in unfolded SPI molecules, forming a mesh structure. However, under alkaline conditions (pH 9), adhesive viscosity and stability increased compared to the original pH. This shift was due to the disruption of the SPI colloidal charge structure, an increase in the stretching of functional groups, further unfolding of the structure, and an enhanced binding of SPI to TA. Under the initial pH conditions, SPI reacted with TA's active site to form covalent crosslinked networks and hydrogen bonds. In alkaline condition, beyond hydrogen and ionic bonding, the catechol structure was oxidized, forming an ortho-quinone that crosslinked SPI and created a denser structure. Tensile strength measurements and freeze-thaw experiments revealed that the adhesive exhibited maximum tensile strength and optimal adhesion with 0.75% TA at pH 9, providing the best overall performance. This study provides a new formulation and approach for developing plant-based meat analogues adhesives.

Inactivation of Salmonella Typhimurium, Escherichia coli, and Staphylococcus aureus in Tilapia Fillets (Oreochromis niloticus) with Lactic and Peracetic Acid through Fogging and Immersion

This study investigated the antimicrobial effects of lactic acid (LA) (3%) and peracetic acid (PA) (300 ppm) on tilapia fillets (Oreochromis niloticus) by fogging (15 min) or by immersion (2 s) in a pool of Escherichia coli (NEWP 0022, ATCC 25922, and a field-isolated strain), Staphylococcus aureus (ATCC 25923 and a field-isolated strain), and Salmonella Typhimurium (ATCC 13311 and ATCC 14028), as well as the effects on the physicochemical characteristics of the fillets. Fogging was effective and the best application method to control S. Typhimurium regardless of the acid used, promoting reductions of 1.66 and 1.23 log CFU/g with PA and LA, respectively. Regarding E. coli, there were significant reductions higher than 1 log CFU/g, regardless of the treatment or acid used. For S. aureus, only immersion in PA showed no significant difference (p < 0.05). For other treatments, significant reductions of 0.98, 1.51, and 1.17 log CFU/g were observed for nebulized PA, immersion, and LA fogging, respectively. Concerning the pH of the samples, neither of the acids used differed from the control. However, treatments with LA, and fogging with PA, reduced the pH compared to immersion in PA. As for color parameters, L* and a* values showed changes regardless of the acid or method used, resulting in an improved perception of fillet quality. These results indicate that fogging and immersion are alternatives for reducing S. Typhimurium, E. coli, and S. aureus in tilapia fillets.

Bactericidal effect of water-washing methods on Vibrio vulnificus contaminated in a raw fish Konosirus punctatus: water type, temperature, and pH

This study aimed to evaluate a method for effectively reducing Vibrio vulnificus contamination in fish based on the type of washing water and method. Texture profiles and sensory evaluations were performed to determine the effect of the developed method on the quality and preference of the samples. The selected fish sample was Konosirus punctatus, which is mainly consumed in Asian countries. Various factors that could affect the survival rate of V. vulnificus were reviewed, including water type, temperature, exposure time, organic acids, pH, and washing methods. As a result, immersion and washing with filtered water with pH adjusted to 4.0 using acetic acid showed a high bactericidal effect of 2.5 log MPN/100 g. Furthermore, this method showed no statistically significant effect on the texture and sensory characteristics of fish. The results of the present study suggest a simple and effective method for preventing V. vulnificus infection in raw fish.

Modern Concepts of Restructured Meat Production and Market Opportunities

Restructured meat (RM) products are gaining importance as an essential component of the meat industry due to consumers' interest in health benefits. RM products imply the binding or holding of meat, meat by-products, and vegetable proteins together to form a meat product with meat's sensory and textural properties. RM products provide consumers with diversified preferences like the intake of low salt, low fat, antioxidants, and high dietary fiber in meat products. From the point of environmental sustainability, RM may aid in combining underutilized products and low-valued meat by adequately utilizing them instead of dumping them as waste material. RM processing technique might also help develop diversified and new hybrid meat products. It is crucial to have more knowledge on the quality issues, selection of binding agents, their optimum proportion, and finally, the ideal processing techniques. It is observed in this study that the most crucial feature of RM could be its healthy products with reduced fat content, which aligns with the preferences of health-conscious consumers who seek low-fat, low-salt, high-fiber options with minimal synthetic additives. This review briefly overviews RM and the factors affecting the quality and shelf life. Moreover, it discusses the recent studies on binding agents in processing RM products. Nonetheless, the recent advancements in processing and market scenarios have been summarized to better understand future research needs. The purpose of this review was to bring light to the ways of sustainable and economical food production.

Improvement of Microbial Quality, Physicochemical Properties, Fatty Acids Profile, and Shelf Life of Basa (Pangasius bocourti) Fillets during Chilling Storage Using Pepsin, Rosemary Oil, and Citric Acid

Meat discoloration, lipid oxidation, and undesirable texture are inevitable phenomena in basa fish fillets during storage, which in turn limits their exportation as well as decreases consumer acceptability. In addition, increasing consumers' requirements for high-quality, minimally processed, and ready-to-cook fish fillets with an extended shelf-life is a great challenge, particularly with lifestyle changes. Accordingly, this study aimed to improve the quality, lipid stability, fatty acid profile, and lipid nutritional quality indices (LNQI) of basa fish fillets during chilling storage at 4 °C for 15 days using pepsin enzyme (E, 0.1%), rosemary oil (R, 0.5%), citric acid (CA, 0.5%), and their combination (0.1% E + 0.5% R; 0.1% E + 0.5% CA; and 0.1% E + 0.5% R + 0.5% CA). Our results revealed that all treated samples exhibited a significant increase in protein content, a significant decrease in fat content, and a marked reduction in pH, total volatile base nitrogen (TVBN), thiobarbituric acid (TBA), free fatty acids, and shear force (SF) values in comparison to control ones. Moreover, significant improvements in sensory scores, color stability, fatty acid profile, LNQI, and microbial quality of all treated samples were observed. Such findings were more pronounced in samples treated with a mixture of pepsin, rosemary, and citric acid (TVBN: 2.04 vs. 6.52 mg%; TBA: 0.40 vs. 2.68 mg malonaldehyde/Kg; and SF: 8.58 vs. 19.51 Kgf). Based on the obtained results, there was an extension for the shelf life of all treated basa fish fillet samples, especially in samples treated with a mixture of pepsin, rosemary, and citric acids when compared with the control samples (˃15 days versus 10 days). Additionally, eucalyptol, camphor, isoborneol, and α-pinene are the main components of rosemary, with great antioxidant and antimicrobial activity. In conclusion, the mixture of pepsin, rosemary, and citric acid can be applied easily in the seafood industry and at the household level to provide ready-to-cook fish fillets of high quality with great health benefits.

Characterization of coacervation behavior between whey protein isolate and gum Arabic: Effects of heat treatment

Currently, the effect of heat treatment on the complex coacervation behavior of whey isolate protein (WPI) with gum arabic (GA) is undiscussed. In this work, the complex coacervation behavior of WPI with or without heat treatment and GA in different environments was investigated. The results showed that coacervates were formed at a mass ratio of 2:1 and a pH of 3.5, which was confirmed by the fluorescence spectroscopy results. Heat treatment increased the surface charge of WPI, reduced the saturated adsorption concentration of GA, and enhanced the sensitivity of the complex coacervation reaction to salt ions. Fourier infrared spectroscopy, intermolecular force analysis and molecular docking results confirm that the formation of coacervates is the result of electrostatic interactions. From the scanning electron microscope and differential scanning calorimetry results, it is clear that the whey isolate protein combined with gum arabic forms a gel-like conjugate with higher thermal stability and a dense structure. This study provides more in-depth theoretical guidance for the application of WPI and GA based coacervation and more advanced theoretical data for the study of hWPI.

Regulation of the Colour Change of 3D-Printed Mackerel Mince (Scomber scombrus) Based on Purple Potato Powder and Citric Acid

The present study evaluates the effect of purple potato (PP) powder and citric acid (CA) on the regulation of the colour change of 3D (three-dimensional) printed mackerel mince (Scomber scombrus). In addition, the effects of PP and CA content on the 3D-printability and quality of mackerel mince were also investigated. The results showed that an increase in PP and CA concentrations gradually brightened the product colour and turned it pink. Furthermore, an increase in PP concentration and added CA reduced the fluidity and loss of water in mackerel mince. Proper PP and CA concentrations moderately increased the storage modulus (G'), loss modulus (G″), and yield stress of mackerel mince, making it suitable for 3D printing. At the same time, an increase in PP and CA concentrations enhanced the umami and sweet taste of mackerel mince but reduced the fishy and sour taste, and the degree of preference was within the acceptable range, except for PP1%-CA0%. It was found that, when the 3D-printing accuracy of mackerel-mince samples reached more than 97% and was acceptable, the optimal PP and CA concentrations for realizing the regulation of L*, a*, and b* were 1.00~3.00% and 0.09~0.32%, respectively.

Limiting Pink Discoloration in Cooked Ground Turkey in the Absence or Presence of Sodium Tripolyphosphate Produced from Presalted and Stored Raw Ground Breasts

The effects of pink inhibiting ingredients (PII) to eliminate the pink color defect in cooked turkey breast produced from presalted and stored raw ground turkey in the absence or presence of sodium tripolyphosphate (STP) were examined. Ground turkey breast was mixed with 2% sodium chloride and vacuum packaged. After storage for 6 d, ten PII were individually incorporated without or with added STP (0.5%) as follows: none (control), citric acid (CA; 0.1%, 0.2%, 0.3%), calcium chloride (CC; 0.025%, 0.05%), ethylenediaminetetraacetic acid disodium salt (EDTA; 0.005%, 0.01%), and sodium citrate (SC; 0.5%, 1.0%). Treatments were cooked at a fast or slow cooking rate, cooled, and stored before analysis. All PII tested were capable of lowering inherent pink color compared to the control (No STP: CIE a* pooled day reduction of 23.0%, 5.2%, 12.6%, and 12.6% for CA, CC, EDTA, and SC, respectively; STP: reduction of 21.5%, 17.4%, 6.0%, and 18.2% for CA, CC, EDTA, and SC, respectively). For samples without STP, fast cooking rate resulted in higher CIE a*. However, slow cooking resulted in more red products than fast cooking when samples included STP. Presalting and storage of ground turkey caused the pink discoloration in uncured, cooked turkey (CIE a* 6.24 and 5.12 for without and with STP). This pink discoloration can be decreased by inclusion of CA, CC, EDTA, or SC, but incorporation of CA decreased cooking yield. In particular, the addition of SC may provide some control without negatively impacting the cooking yield.

Chitosan Gel Prepared with Citric Acid as the Food Acidulant: Effect of the Chitosan Concentration and Gel pH on Physicochemical and Functional Properties of Fish Protein Emulsion Sausages

Citric acid is a popular food acidulant with versatile utility as a preservative and acidity regulator in the meat industry, owing to its unique three pK _a values, which can be combined with the natural biopolymer chitosan to improve food quality. The scientific incorporation of a minimal range of chitosan and pH through organic acid additions for chitosan solubilization in the fish sausages can effectively improve their quality through their synergistic effect. Optimum conditions for emulsion stability, gel strength, and water holding capacity were found to be at a low concentration of chitosan, that is, 0.15 g at pH of 5.0, with their corresponding values of 42.55 ± 0.43 N mm, 94.91 ± 0.24, and 90.67 ± 0.50%. Lower pH ranges increased hardness and springiness values, and higher pH levels increased cohesiveness values at varying ranges of chitosan. Sensory analysis revealed tangy and sour flavors in the samples with lower pH.