Modelling of the kinetics of Bovine Serum Albumin enzymatic hydrolysis assisted by high hydrostatic pressure

Effects of physical processing on food protein allergenicity: A focus on differences between animal and alternative proteins

In recent years, physical technologies have been widely employed to reduce food protein allergenicity due to their simplicity and stability. This paper summarizes recent research advances in these technologies, focusing on differences in their effects on allergenicity between animal and alternative proteins. The mechanisms of allergenicity reduction and the advantages and disadvantages of these technologies were compared. It was found that heating, although affording better allergenicity reduction than non-thermal treatment technologies, affects other properties of the food. Because of their higher molecular weights and more complex structures, animal proteins are less affected by physical technologies than alternative proteins. It is worth noting that there is a scarcity of existing technology to reduce the allergenicity of food proteins, and more technologies should be explored for this purpose. In addition, better allergenicity-reducing processing technologies should be designed from the perspectives of processing conditions, technological innovations, and combined processing technologies in the future.

Transformation of Seafood Side-Streams and Residuals into Valuable Products

Seafood processing creates enormous amounts of side-streams. This review deals with the use of seafood side-streams for transformation into valuable products and identifies suitable approaches for making use of it for different purposes. Starting at the stage of catching fish to its selling point, many of the fish parts, such as head, skin, tail, fillet cut-offs, and the viscera, are wasted. These parts are rich in proteins, enzymes, healthy fatty acids such as monounsaturated and polyunsaturated ones, gelatin, and collagen. The valuable biochemical composition makes it worth discussing paths through which seafood side-streams can be turned into valuable products. Drawbacks, as well as challenges of different aquacultures, demonstrate the importance of using the various side-streams to produce valuable compounds to improve economic performance efficiency and sustainability of aquaculture. In this review, conventional and novel utilization approaches, as well as a combination of both, have been identified, which will lead to the development of sustainable production chains and the emergence of new bio-based products in the future.

Alteration of the allergenicity of cow's milk proteins using different food processing modifications

Milk is an essential source of protein for infants and young children. At the same time, cow's milk is also one of the most common allergenic foods causing food allergies in children. Recently, cow's milk allergy (CMA) has become a common public health issue worldwide. Modern food processing technologies have been developed to reduce the allergenicity of milk proteins and improve the quality of life of patients with CMA. In this review, we summarize the main allergens in cow's milk, and introduce the recent findings on CMA responses. Moreover, the reduced effects and underlying mechanisms of different food processing techniques (such as heating, high pressure, γ-ray irradiation, ultrasound irradiation, hydrolysis, glycosylation, etc.) on the allergenicity of cow's milk proteins, and the application of processed cow's milk in clinical studies, are discussed. In addition, we describe the changes of nutritional value in cow's milk treated by different food processing technologies. This review provides an in-depth understanding of the allergenicity reduction of cow's milk proteins by various food processing techniques.

Advanced Tenderization of Brine Injected Pork Loin as Affected by Ionic Strength and High Pressure

This study investigated the effects of brine injection and high hydrostatic pressure (HHP) on the quality characteristics of pork loin. Brine with ionic strength conditions (0.7% vs 1.5% NaCl, w/v) were injected into pork loins, and the meat was pressurized up to 500 MPa for 3 min. As a quality indicator, moisture content, color, cooking loss and texture profile analysis (TPA) of pork loins were estimated. Based on the results, brine with low ionic strength (0.7% NaCl) resulted in low injection efficiency and high cooking loss, although, it improved tenderness of pork loin at moderate pressure level (~200 MPa). While high ionic strength condition (1.5% NaCl injection) lowered the hardness of pork loins at relatively high HHP level (400-500 MPa), it also caused high cooking loss. To commercialize the brine injected pork loins, it was necessary to regulate brine compositions, which was not evaluated in this study. Nevertheless, the present study demonstrated that brine injection followed by moderate pressure (200 MPa) could improve the tenderness of pork loins without causing other major quality losses.

Release principle of peptides and amino acids during the autolysis of shrimp head from Litopenaeus vannamei after UV-C irradiation stress

UV-C irradiation can activate endogenous enzymes in the body of many aquatic animals. Autolysis kinetics of shrimp head after UV-C irradiation stress was investigated. During the first 5 hr of autolysis, the release of the autolysis products was in line with the first-order equations of the reaction rate: Y = 37.681e-0.173 t , Pe = -1.769Y + 74.156, and TP = -1.5117Y + 60.866. A good linear correlation was founded between the release of total protein and that of products with molecular weight of 3,000 Da after these products associated with residual total protein were autolyzed. In contrast to the inconsistent effect of substrate concentration on autolysis rate constants, the effects of pH and temperature on the autolysis rate constants of shrimp head showed a consistent pattern. An Arrhenius equation (lnKa = 8,090.2/T - 26.497) was established to validate the proposed autolysis kinetic equations. The autolysis rate of products with molecular weight < 3,000 Da increased rapidly from 0 hr to 3 hr. The aliphatic amino acids showed a higher amount release than that of other amino acids during the autolysis. The amounts of released heterocyclic amino acids (Trp and His) were also much more than that of other amino acids.

Effects of ultra-high pressure on effective synthesis of fructooligosaccharides and fructotransferase activity using Pectinex Ultra SP-L and inulinase from Aspergillus niger

In this study, various levels of ultra-high pressure (UHP) were combined with the enzymatic synthesis of the fructooligosaccharide (FOS) using Pectinex Ultra SP-L and inulinase. The combination enhanced the FOS yields up to 2.5- and 1.5-fold, respectively, compared to atmospheric condition (0.1 MPa). However, the enzymatic reaction was dependent on the levels of pressure, the reaction times, and the initial sucrose concentrations. The combined UHP and inulinase showed that the maximum FOS yield (71.81%) was obtained under UHP at 200 MPa for 20 min with 300 g/L of initial sucrose as a substrate, while the FOS yield (57.13%) using Pectinex Ultra SP-L was obtained under UHP at 300 MPa for 15 min with 600 g/L of initial sucrose as a substrate. The FOS composition produced by Pectinex Ultra SP-L under the UHP was 1-kestose (GF₂), nystose (GF₃), and 1F-fructofuranosylnystose (GF₄), whereas the FOS produced by inulinase composed of only GF₂ and GF₃. The combined UHP is a useful tool in the industrial application for FOS production. Highlights UHP activated the activity of Pectinex Ultra SP-L yet inactivated inulinase Pressure level, time, and sucrose concentration significantly affect FOS yields under UHP UHP enhanced FOS production with time-saving benefits within 15-20 min.

Bromelain Kinetics and Mechanism on Myofibril from Golden Pomfret (Trachinotus blochii)

Bromelain was used to tenderize golden pomfrets (Trachinotus blochii). The enzyme kinetic model was x=2.447×ln[1+(1332.21×E0S0-1.74)t], which indicated that the degree of hydrolysis (DH, x) was dependent on hydrolysis time (t), the initial concentration of myofibril (S₀ ) and bromelain (E₀ ). The relationship between the overall hydrolysis rate (v), S₀ , E₀ , and t is demonstrated as: v=(16.50(E0S0)-1.33)S0 exp {-2.447ln[1+(1332.21E0S0-1.74)t2]}. Sample of 0.40% E₀ /S₀ was further used to study the effects of hydrolysis time on the changes of proteins, peptides, free amino acids (FAA), and protein nanostructure. SDS-PAGE result showed that myosin heavy chain was degraded dramatically from 22.88% before treatment to 12.03% after 2 min bromelain treatment. Meanwhile, bromelain did not exhibit activity towards actin, trypomyosin, myosin light chain, and troponin C. A general increase of amino acids indicated the increased DH and the preferential cleavage sites of bromelain in the descending order of lysine, glutamic acid, glycine, ornithine, methionine sulfoxide, and alanine. Atomic force microscope images showed that the strip-like structure of myofibril was considerably degraded by bromelain, and the granulation of protein after 20 min indicated possible self-assembling of protein hydrolysate. Confocal laser scanning microscopy further confirmed the degradation of myofibril proteins and formation of protein aggregates.

PRACTICAL APPLICATION

Meat of golden pomfrets is tough, thus not idea for fish balls or fish cakes. Tenderization is essential to achieve desired texture and consumer acceptance, especially for this fish meat with intrinsic hard texture. Bromelain can be extracted from pineapple processing waste. Enzymatic kinetics was studied to instruct industry to control the tenderness of the processed fish meat. The microstructural and mechanism study elucidate the process, thus could be applied to improve the quality of the seafood products correspondingly.