Pulsed electric field: Role in protein digestion of beef Biceps femoris

The present study was conducted to evaluate the effect of pulsed electric field (PEF) on the protein digestion kinetics of cold-boned beef Biceps femoris during in-vitro simulated gastrointestinal digestion. Muscle was treated with PEF at 5 kV, 90 Hz, 20 μs (T₁) and 10 kV, 20 Hz, 20 μs (T₂) and subjected to in-vitro gastrointestinal digestion along with an untreated control. Samples were collected at 0, 30, and 60 min of gastric digestion and 120 and 180 min of intestinal digestion. PEF processing affected the digestion kinetics by modifying the protein profile (SDS-PAGE) of the meat digests and significantly (P  0.05) impact was observed on the release of minerals such as Fe, Zn, Cr, Cu, Mg, Ni, Na or K. PEF processing improved the digestion kinetics of the beef muscle during gastrointestinal digestion simulation. Industrial relevance: PEF processing has already been reported to improve the tenderization of beef muscles during ageing process. The simulations and experiments conducted in this work showed that PEF processing has the potential to improve the protein digestion kinetics of beef muscle during in-vitro gastrointestinal digestion and could be utilized for the development of novel muscle foods and protein structures with improved digestibility and nutritive value

Pulsed electric field improved protein digestion of beef during in-vitro gastrointestinal simulation

Effect of pulsed electric field (PEF) on in-vitro simulated gastrointestinal protein digestion of cold-boned beef Semimembranosus was elucidated. PEF treated [T₁, 5.0 kV (90 Hz); T₂, 10 kV (20 Hz)] samples along with control were subjected to in-vitro simulated gastrointestinal protein digestion. Samples collected at 0, 30 and 60 min of gastric digestion and 120 and 180 min of intestinal digestion were analysed for protein digestibility (%), soluble protein (%), protein profile (SDS-PAGE), free amino acid analysis and mineral profile. Significantly higher (P 0.05) of PEF was observed on the release of various minerals from the muscle during the digestion. By modifying the protein profile of the meat digests, PEF processing had a positive influence on in-vitro digestion kinetics that led to a faster and greater digestion of proteins during simulated gastrointestinal digestion

Physicochemical properties and bioactivity of extracts from the roe of New Zealand hoki and southern blue whiting

Various physicochemical properties of New Zealand hoki and southern blue whiting (SBW) roes and the biological activities of their extracts were investigated. Protein, moisture, and ash contents in both roes were similar; however, the lipid content of hoki roe was higher (p < 0.05) than SBW roe (11.0 ± 0.9 and 2.5 ± 0.1, respectively). Both fish roe extracts contained active protease inhibitors toward trypsin and papain. Neither of the roe extracts agglutinated erythrocytes, indicating the absence of lectins. Both fish roe extracts at 5 mg/mL concentration exhibited slight inhibitory effects on the proliferation of breast cancer cells, but neither of the roe extracts exhibited RNase or antifungal activity

Nutritional and toxicological studies of New Zealand Cookia sulcata

Interest in snails as a source of protein and as a delicacy is increasing in many countries. The present study investigated selected nutritional (proximate, amino acid, fatty acid, vitamin E, cholesterol and macro- and trace minerals) and toxic (toxic elements and organochlorine) concentrations of small and large (≤60 and > 60. g whole animal weight, respectively) Captain Cook snails (Cookia sulcata). The major amino acids in C. sulcata muscle were glutamic (13.9. g/100. g protein), arginine (10.2. g/100. g protein), glycine (9.5. g/100. g protein) and taurine (9.5. g/100. g protein). There was no difference in the amino acid profiles related to the snail size. C. sulcata had relatively high amounts of saturated fatty acids (44.4%) and polyunsaturated fatty acids (34.3%), and lesser amounts of mono-unsaturated fatty acids. The major fatty acids detected in C. sulcata were C16:0, C18:0, C20:4 and C22:5, which accounted for more than 60% of the total fatty acids. Snail size had a significant (P < . 0.05) effect on the C16:0 and C18:3 concentrations. The only isoform of vitamin E present in C. sulcata was identified as α-tocopherol at 2.16 and 3.71. mg/100. g fresh weight for the small and large snails, respectively. The average cholesterol concentration in C. sulcata was 1.33. mg/100. g fresh weight. The results indicated that none of the toxic elements, including Al, Ni, As and Pb of C. sulcata, were over the maximum concentration allowed in the Australia New Zealand Food Standard; and the organochlorine pesticides concentrations in C. sulcata were below the detection limit ( < 0.0005. mg/kg). C. sulcata could, therefore, be utilized for special dietary applications requiring higher amounts of Fe, Zn, taurine and tryptophan

Current and future prospects for the use of pulsed electric field in the meat industry

Pulsed electric field (PEF) is a novel non-thermal technology that has recently attracted the attention of meat scientists and technologists due to its ability to modify membrane structure and enhance mass transfer. Several studies have confirmed the potential of pulsed electric field for improving meat tenderness in both pre-rigor and post-rigor muscles during aging. However, there is a high degree of variability between studies and the underlying mechanisms are not clearly understood. While some studies have suggested physical disruption as the main cause of PEF induced tenderness, enzymatic nature of the tenderization seems to be the most plausible mechanism. Several studies have suggested the potential of PEF to mediate the tenderization process due to its membrane altering properties causing early release of calcium ions and early activation of the calpain proteases. However, experimental research is yet to confirm this postulation. Recent studies have also reported increased post-mortem proteolysis in PEF treated muscles during aging. PEF has also been reported to accelerate curing, enhance drying and reduce the numbers of both pathogens and spoilage organisms in meat, although that demands intense processing conditions. While tenderization, meat safety and accelerated curing appears to be the areas where PEF could provide attractive options in meat processing, further research is required before the application of PEF becomes a commercial reality in the meat industry. It needs to deal with carcasses which vary biochemically and in composition (muscle, fat, and bones). This review critically evaluates the published reports on the topic with the aim of reaching a clear understanding of the possible applications of PEF in the meat sector in addition to providing some insight on critical issues that need to be addressed for the technology to be a practical option for the meat industry

Nutritional composition of Mutton bird (Puffinus griseus) meat

Mutton birds (Puffinus griseus) are wild seabird chicks traditionally harvested by Maori but available commercially for seasonal consumption in New Zealand. Little information is available on the nutritional content of the meat from these birds. Proximate analysis and amino and fatty acid composition of Mutton bird breast meat (MBBM) were measured over two harvesting seasons, 2007 and 2008. Protein content was lower, and fat and ash contents were higher (P < 0.05) in meat from birds harvested in 2008 (18.5, 13.0 and 11.7%, respectively) compared with that from 2007 (20.3, 11.8 and 10.3%, respectively). Higher lysine concentrations and lower proline, cysteine and methionine were found in MBBM compared with literature values for beef, lamb and pork. The essential amino acid content in Mutton bird (41.7 and 38.4% for 2008 and 2007, respectively) was slightly lower than those reported for common meats (42–43%). Palmitic, arachidonic, DHA, stearic, EPA, and oleic were the major fatty acids (FA) detected in MBBM and accounted for approximately 60% of the FA. The cholesterol concentration was not affected by season. Seasonal variations MBBM existed which may be of little nutritional consequence but might be a useful indicator for ecological events including changing feed availability

Fractionation of whey proteins from red deer (Cervus elaphus) milk and comparison with whey proteins from cow, sheep and goat milks

In the present study, we report the first protein fractionation analysis of whey proteins from red deer (Cervus elaphus) milk. The aim of this study was to investigate the protein composition of red deer milk and examine the protein profile compared with that of cow, sheep and goat using 1D-PAGE and protein RP-HPLC of defatted milk. Ammonium sulfate fractionated sweet whey proteins of the four species were further subjected to anion exchange chromatography, and 1D- and large format 2D-PAGE analysis. Deer milk caseins displayed different mobility on 1D-PAGE, and chromatographed differently on RP-HPLC to those of other species. The apparent ratio of alpha-lactalbumin to beta-lactoglobulin in red deer milk was different compared to other species. As cheese wheys from other ruminants have been shown to contain proteins and peptides with health promoting benefits, it is of interest to characterize proteins in red deer whey, a by-product of an emerging novel deer cheese manufacture venture. Red deer sweet whey, as well as other species, could be fractionated to obtain a fraction partially depleted of alpha-lactalbumin and beta-lactoglobulin, which facilitated display of lower abundance proteins by 1D- and 2D-PAGE. Furthermore, a difference in casein coagulation during sweet whey production from milks of red deer and other species was observed

Effect of processing technologies on the digestibility of egg proteins

Egg and egg products are a rich source of highly bioavailable animal proteins. Several processing technologies can affect the structural and functional properties of these proteins differently and can influence their fate inside the gastrointestinal tract. The present review examines some of the processing technologies for improving egg protein digestibility and discusses how different processing conditions affect the digestibility of egg proteins under gastrointestinal digestion environments. To provide up-to-date information, most of the studies included in this review have been published in the last 5 years on different aspects of egg protein digestibility. Digestibility of egg proteins can be improved by employing some processing technologies that are able to improve the susceptibility of egg proteins to gastrointestinal proteases. Processing technologies, such as pulsed electric field, high-pressure, and ultrasound, can induce conformational and microstructural changes that lead to unfolding of the polypeptides and expose active sites for further interactions. These changes can enhance the accessibility of digestive proteases to cleavage sites. Some of these technologies may inactivate some egg proteins that are enzyme inhibitors, such as trypsin inhibitors. The underlying mechanisms of how different technologies mediate the egg protein digestibility have been discussed in detail. The proteolysis patterns and digestibility of the processed egg proteins are not always predictable and depends on the processing conditions. Empirical input is required to tailor the optimization of processing conditions for favorable effects on protein digestibility

Sous-vide cooking improves the quality and in-vitro digestibility of Semitendinosus from culled dairy cows

Effect of sous-vide processing was evaluated on in-vitro simulated protein digestion, myofibrillar protein profile, lipid oxidation and physicochemical properties of cold-boned beef Semitendinosus. Sous-vide processed [T1, 60 °C (4.5 h); T2, 60 °C (10 h)] samples along with control beef (cooked at 80 °C until a core temperature of 75 °C was attained) were subjected to in-vitro simulated gastrointestinal protein digestion. Samples collected at 0, 30 and 60 min of gastric digestion and 120 and 180 min of intestinal digestion were analysed for protein profile (SDS-PAGE), protein digestibility (%), soluble protein (%), free amino acid analysis and mineral profile. A significant (P < 0.05) decrease was observed in shear force (N) and cooking loss (%) of sous-vide processed samples in comparison to control whereas a significant (P < 0.05) increase was observed in colour (L*, a*, b*). A significant (P < 0.05) increase was also observed in protein digestibility (%), soluble protein (%) and release of free amino acids and minerals from sous-vide processed samples during in-vitro digestion. By modifying the protein profile of the meat, sous-vide processing had a positive influence on in-vitro digestion kinetics that led to a greater and faster digestion of proteins during simulated digestion