Use of proteases to improve oxidative stability of fermented sausages by increasing low molecular weight compounds with antioxidant activity

Research Progress on the Mechanism of the Impact of Myofibrillar Protein Oxidation on the Flavor of Meat Products

Myofibrillar proteins primarily consist of myosin, actin, myogenin, and actomyosin. These proteins form complex networks within muscle fibers and are crucial to the physical and chemical properties of meat. Additionally, myofibrillar proteins serve as significant substrates for the adsorption of volatile flavor compounds, including aldehydes, alcohols, ketones, and sulfur and nitrogen compounds, which contribute to the overall flavor profile of meat products. A series of chemical reactions occur during the processing, storage, and transportation of meat products. Oxidation is one of the most significant reactions. Oxidative modification can alter the physical and chemical properties of proteins, ultimately impacting the sensory quality of meat products, including flavor, taste, and color. In recent years, considerable attention has been focused on the effects of protein oxidation on meat quality and its regulation. This study investigates the impact of myofibrillar protein oxidation on the sensory attributes of meat products by analyzing the oxidation processes and the factors that initiate myofibrillar protein oxidation. Additionally, it explores the control of myofibrillar protein oxidation and its implications on the sensory properties of meat products, providing theoretical insights relevant to meat processing methods and quality control procedures.

Application of a crude digestive proteases preparation to improve the ripening of marinated fillets from low-technological value Baltic herring (Clupea harengus membras L.)

BACKGROUND

As a result of climate change (reduced the oxygen content and food available in the waters) and overfishing, ever larger batches of the herring catch are classified as low-value fish and used for feedstuff or canned food production. Fast and complete ripening of marinated fillets, especially from low-value Baltic herring, poses a problem because of the low muscle protease activity and changes in muscle tissue proteins.

RESULTS

For the first time, a crude digestive proteases preparation (CDPP) was obtained from herring viscera using a two-stage method consisting of ethanol extraction and then salt precipitation. CDPP had a reduced hemoglobin content, with optimum activity at pH 7.5-8.8 or 60-120 g kg-1 NaCl. At pH 4-5, it still exhibited 24-68% of proteolytic activity. CDPP was used for 4-24 h of brining of fresh and frozen-thawed fillets or injection of fresh fillets before marinating. CDPP-brining increased especially cathepsin D and carboxypeptidase A activities, whereas it decreased cathepsin B and L activities in the marinades. CDPP-brining mitigated the negative effect of freezing-thawing on mass-yield, protease activity, protein hydrolysis, texture profile, colour and sensory quality of the marinated fillets. CDPP-injection was found to be the best method because it increased mass-yield and ripeness of the marinated fillets to a greater extent than CDPP-brining did. The marinades from the CDPP-treated fillets had no bitter taste as a result of the presence of hemoglobin or chymotrypsin, and there were no results indicating lipid oxidation.

CONCLUSION

The application of CDPP in marinating technology is a viable approach to enable the use of low-value herring in food production, shorten the marinating time, and improve the ripeness and sensory quality of meat. © 2024 Society of Chemical Industry.

Preliminary research on the flavor substance and antioxidant capacity of beers produced with baking Qingke

The addition of baked Qingke improves the flavor profile of beer. In this study, beer was brewed using Qingke baked at various temperatures. The beer produced with Qingke baked at 180 °C achieved the highest sensory score (40/50), an alcohol content of 6.92% (v/v), a total phenolic content of 446.42 mg/L, melanoidin concentration of 98.22 g/L, a color value of 10.88 EBC, and exhibited satisfactory antioxidant activity. Analysis of volatile compounds using HS-SPME-GC-MS revealed 48 compounds, of which esters accounted for 63% and alcohols accounted for 27% of the total content. The flavor profile of the beer varied across different baking temperatures. Pyrazines and aldehydes were predominantly present in samples baked at higher temperatures (T3, T4, and T5). Correlation analysis showed that the baking flavor in the beer was primarily correlated with 2, 5-dimethyl-pyrazine, trimethyl-pyrazine, phenylacetaldehyde, and ethyl 9-decenoate (R > 0.9).

Antioxidant Activity of Aqueous Extracts Obtained from By-Products of Grape, Olive, Tomato, Lemon, Red Pepper and Pomegranate

The aim of this work was to study the antioxidant potential of aqueous extracts obtained from different by-products. The effectiveness of these extracts was compared with that of rosemary extract. Total phenol carotenoid and vitamin C contents, as well as in vitro antioxidant activity, were assessed. Phenol content was positively correlated with in vitro antioxidant activity in extracts, while carotenoids showed a less clear relationship. Vitamin C was associated with antioxidant activity in lemon and pepper pomace extracts. Extracts from olive, grape, and lemon by-products displayed the highest antioxidant activity (radical scavenging activity), this being similar to the activity of rosemary extracts. Moreover, the phenolic profile of the extracts was analyzed, revealing diverse phenolic compounds. Rosemary extracts contained the highest variety and quantity of phenolic compounds, while olive pomace extracts were rich in hydroxytyrosol and 4-hydroxybenzoic acid. Lemon and pepper extracts contained high amounts of tyrosol, and tomato extracts had abundant epicatechin. The PCA analysis distinguished extracts based on in vitro antioxidant activity, phenol, carotenoid, and vitamin C content, along with their phenolic compound profiles. This study emphasizes the capacity of aqueous extract by-products as valuable sources of antioxidants and highlights the importance of understanding their bioactive components.

Inclusion of exogenous enzymes in feedlot cattle diets: Impacts on physiology, rumen fermentation, digestibility and fatty acid profile in rumen and meat

The objective of this study was to evaluate if the inclusion of a blend composed of exogenous enzymes (amylase, protease, cellulase, xylanase and beta glucanase) in the individual and combined form in the feedlot steers diet has benefits on the physiology, rumen fermentation, digestibility and fatty acid profile in rumen and meat. The experiment used 24 animals, divided into 4 treatments, described as: T1-CON, T2-BLEND (0.5 g mixture of enzyme), T3-AMIL (0.5 g alpha-amylase), T4-BLEND+AMIL (0.5 g enzyme blend+ 0.5 g amylase). The concentration of mineral matter was higher in the meat of cattle of T4-BLEND+AMIL. A higher proportion of monounsaturated fatty acids was observed in the T3-AMIL group when compared to the others. The percentage of polyunsaturated fatty acids was higher in the T2-BLEND and T4-BLEND+AMIL compared to the T1-CON. The combination of exogenous enzymes in the diet positively modulate nutritional biomarkers, in addition to benefits in the lipid and oxidative profile meat.

Effect of mashing temperature on fermentation and antioxidant capacity of Qingke wort

Background and Objectives

Mashing temperature is important during beer brewing processes. Qingke malt was a new material whose application in the beer industry holds significant importance for the beer industry and agriculture development in the Qinghai–Tibet Plateau. The objective of this study was to investigate the effects of mashing temperature on the physicochemical parameters, fermentation capacity, and antioxidant capacity of Qingke wort.

Findings

Ethanol production and the real degree of fermentation decreased with increasing the temperature—S, while the real extract increased with increasing the temperature—S. A lower temperature—S proved to be more advantageous for the fermentation capacity of Qingke wort. In addition, a positive correlation between reducing power and the temperature—P and a negative correlation between the 2,2′‐azinobis‐(3‐ethylbenzothiazoline‐6‐sulfonate) free radical scavenging activity and the temperature—S were found.

Conclusion

The fermentation capacity of Qingke wort was obtained the best when the temperature—P was 50°C and the temperature—S was 60°C. The antioxidant capacity of Qingke wort was satisfactory; the best was obtained when the temperature—P was 45°C and the temperature—S was 60°C.

Significance and Novelty

This is the first study to investigate the mashing characteristics of Qingke wort under different mashing temperatures. The results show that β‐glucan content was abundant in Qingke wort and was positively correlative with the temperature—S.

Purification of Extracellular Protease from Staphylococcus simulans QB7and Its Ability in Generating Antioxidant and Anti-inflammatory Peptides from Meat Proteins

Proteases, especially microbial proteases, are widely used in food processing. The purpose of this study was aimed to purify an extracellular protease produced by the strain Staphylococcus simulans QB7 and to evaluate its ability in hydrolyzing meat proteins and generating antioxidant and anti-inflammatory peptides. The optimal conditions for producing the enzyme were as follows: inoculum ratio, 10%; initial pH, 6.5; temperature, 32 °C; incubation time, 36 h; and rotation speed, 160 rpm. The protease had a molecular weight of approximately 47 kDa, possessing the optimal activity at 50 °C, pH 7.0, The protease was stable at pH 4.0-8.0 and 30-60 °C, and the activity was improved by Na⁺, Mg²⁺, Ca²⁺, and Zn²⁺ ions, whereas it was inhibited by Cu²⁺, Co²⁺, Fe³⁺, Ba²⁺, Fe²⁺, β-M, and ethylene diamine tetraacetic acid disodium salt (EDTA). The protease could effectively hydrolyze meat proteins, and the generated hydrolysate could significantly inhibit tumor necrosis factor-alpha (TNFα)-induced oxidative stress, including superoxide and malondialdehyde levels and inflammation (vascular adhesion molecule-1 [VCAM-1] and cyclooxygenase 2 [COX2)) in human vascular EA.hy926 cells. The present findings support the ability of S. simulans QB7 protease in generating antioxidant and anti-inflammatory peptides during the fermentation of meat products.

Effect of Phenolic Compounds from Almond Skins Obtained by Water Extraction on Pork Patty Shelf Life

The extraction of phenols from almond skin using water has not been applied before. The purpose of this study was to obtain aqueous extracts from almond skin to be added to pork patties to prolong their shelf life. Four different varieties of almonds were studied and aqueous extracts were obtained. The antioxidant capacity and composition of phenol compounds of the extracts were determined. Results showed that the use of water produces extracts with phenol compounds and antioxidant capacity, with the Antoñeta variety presenting the best performance in terms of antioxidant behavior. The most abundant phenolic compounds identified were isorhamentin-3-O-rutinoside, catechin and protocatechuic acid, all of them had a hydrophilic character due to the -OH groups in their molecules. The effect of almond skin extracts (ALMOND) on the shelf life of pork patties was compared with the effects of a control without extract (CONTROL NEG) and a control with sodium ascorbate (CONTROL POS). Throughout storage, values of pH, weight loss, headspace composition, color, TBARs and psychrotrophic aerobic bacteria were studied. CONTROL POS samples showed the lowest lipid oxidation values in comparison to CONTROL NEG or ALMOND extract samples.

Effect of the protease from Staphylococcus carnosus on the proteolysis, quality characteristics, and flavor development of Harbin dry sausage

The effect of the addition of different levels of S. carnosus protease (0, 0.15, 0.30, 0.45 and 0.60 g/kg raw meat) on the proteolysis, quality characteristics, and flavor development of Harbin dry sausage was investigated. The results showed that the S. carnosus protease addition to Harbin dry sausage effectively promoted the degradation of meat proteins into peptides and free amino acids, thus resulting in tenderization and inhibiting fat oxidation. Moreover, the S. carnosus protease addition could promote the development of key flavor compounds such as some ketones, acids and esters. Sausage with S. carnosus protease levels of 0.45 g/kg exhibited the most attractive sensory attributes. Molecular docking showed that the S. carnosus protease can interact with myosin heavy chains. In summary, the S. carnosus protease addition can improve quality characteristics and flavor profile of Harbin dry sausage.

The impact of Flavourzyme on flavor, antioxidant activity, and sensory attributes of salted grass carp by brine injection and brining

BACKGROUND

Enzyme injection is vital for improving the sensory attributes and processing characteristics of meat products by enhancing proteolysis. However, studies regarding the appropriate dose addition for accelerating protein degradation in grass carp are minimal. This study aimed to investigate the impact of Flavourzyme® on the flavor quality and antioxidant activity of salted grass carp via brine injection and brining.

RESULTS

Flavourzyme was added at doses of 0, 5, 10, 20, and 30 leucine aminopeptidase units (LAPU) per kilogram of raw meat. The results indicated that adding Flavourzyme promoted proteolysis, which was reflected by the enhanced total free amino acid content (from 3.7414 g kg^-1 to 4.9160 g kg^-1 in the brining group and from 3.8039 g kg^-1 to 5.4061 g kg^-1 in the injection group) and a decrease in salt soluble and insoluble protein (P < 0.05). The antioxidant activity was improved, and the thiobarbituric acid reactive substance value in salted carp decreased due to the higher content of the protein hydrolysis product (P < 0.05). All sensory attributes were improved significantly, especially when using brine injection (P < 0.05). Brine injection was helpful to diffuse the Flavourzyme, resulting in stronger proteolysis.

CONCLUSION

The appropriate Flavourzyme dose was 10 LAPU kg^-1 in the injection group and 20 LAPU kg^-1 in the brining group. Therefore, moderate Flavourzyme addition was excellent in improving sensory attributes and storage characteristics, whereas injection represented a novel method to obtain a similar fish meat quality in a shorter time and with less added Flavourzyme. © 2021 Society of Chemical Industry.

An overview on antioxidant peptides from rice bran proteins: extraction, identification, and applications

Rice by-products, generated through the milling processes, have recently been recognized as a potential source of bioactive compounds, such as proteins, essential amino acids, and phenolics. Owing to their antioxidant capacity (which improve the storage stability of foods), these compounds have gained much attention because of their beneficial impacts on human health. It has to be noted that large quantities of rice by-products are not efficiently utilized, which may result in industrial wastes and environmental consequences. Thence, the aim of this review is to provide a comprehensive insight on the antioxidant capabilities, extraction, identification, functional attributes, and applications of bioactive hydrolysates and peptides derived from rice bran protein. This overview would provide an insight on rice bran proteins, which are abundant in bioactive peptides, and could be used as value-added products in food and pharmaceutical applications. Inclusion of bioactive peptides to prevent food spoilage while maintaining food safety has also been highlighted.

Optimization of Extraction Conditions to Improve Phenolic Content and In Vitro Antioxidant Activity in Craft Brewers' Spent Grain Using Response Surface Methodology (RSM)

Extraction temperature, extraction time and liquid (water) to solid ratio were optimized in order to extract antioxidant phenolic compounds from brewers’ spent grain (BSG). The extracts were analysed for their total phenol content (TPC) and antioxidant activity was measured using three different methods: 2,2-diphenyl-2-picrylhydrazyl (DPPH) free radical, 2,2′-azino-bis(3-ethylbenothiazoline-6-sulphonic acid) (ABTS), and reducing power (RP) assays. All the parameters except extraction time promoted different efficiencies for the extraction of antioxidant phenolic compounds. TPC extraction was higher at lower temperatures and lower liquid/solid ratios up to a certain point. In this sense, a decrease in TPC with increasing liquid/solid ratios took place until a 16:1 ratio and a plateau was reached beyond that ratio. The highest DPPH activity was reported for 30–35 °C and 60–90 min extraction and 60–90 min extraction with a 25 mL/g ratio. ABTS values increased as the liquid to solid ratio decreased, being positively correlated with TPC (R = 0.788; p < 0.01). The highest RP was achieved at 30–33 °C extraction temperature and 10–14 mg/mL v/w ratio and at 116–120 min extraction and 16–17 mg/mL ratio. Gallic acid accounted for the majority of the phenolic compounds found, followed by hydroxyphenylacetic acid, epicatechin, and protocatechuic acid. Sinapic, 4-hydroxy benzoic, and syringic acids were also found in lower quantities. Coumaric, vanillic, ferulic, and caffeic acids were present in very small amounts. All the extracts contained phenolics and showed in vitro antioxidant activity, but the extracts obtained by using 30 °C, 121.9 min, and 10 mL/g liquid/solid ratio exhibited the highest content in TPC and antioxidant potential. The aqueous extraction of a potentially bioactive extract from BSG was demonstrated to be an efficient and simple method to recover these value-added compounds.

Feruloylated Arabinoxylans from Nixtamalized Maize Bran Byproduct: A Functional Ingredient in Frankfurter Sausages

Feruloylated arabinoxylans obtained from nixtamalized maize bran were evaluated in terms of physicochemical characteristics and antioxidant capacity when incorporated in frankfurter sausages. Concentrations of 0.15% and 0.30% of feruloylated arabinoxylans were incorporated in frankfurter sausages formulations and a control without feruloylated arabinoxylans was also prepared. Shear force, hardness, color measurement, proximate analysis, pH, titratable acidity, water-holding capacity, total phenols, and antioxidant capacity were evaluated. Phenolic content and antioxidant capacity were significantly higher (P < 0.0001) in all treatments, sausages containing feruloylated arabinoxylans compared to the control. The results showed that there was a significant difference (P < 0.0001) in total phenolic content and antioxidant capacity with all feruloylated arabinoxylans sausages treatments higher than control. Additionally, significant differences (P < 0.0001) were obtained in the physicochemical parameters.

Food by-products as potential antioxidant and antimicrobial additives in chill stored raw lamb patties

The aim of this work was to study the in vitro antioxidant potential of aqueous extracts obtained from tomato (TOM), red grape (GRA), olive (OLI) and pomegranate (POM) by-products as well as to evaluate the effect of their addition into lamb meat patties (1000mg/kg) in order to improve shelf life. A negative (CON) and a positive control (sodium ascorbate, ASC) were also included in the experiment. Results for radical scavenging activity, metal chelating activity and reducing power indicated that GRA and OLI extracts could inhibit oxidation more efficiently than POM and TOM extracts (P<0.01). Consistently, GRA and OLI treatments showed the highest redness (a*) (P<0.01) and antioxidant activity, both for lipids and proteins, throughout storage (P<0.001). Furthermore, in general, microbial counts were reduced by the addition of by-products extracts. These results suggest that the extracts obtained from grape and olive pomaces could be effectively used to replace sodium ascorbate in lamb meat products.

Protein oxidation affects proteolysis in a meat model system

The effect of hydrogen peroxide-induced protein oxidation and pH (4.8 and 5.2) on meat proteolysis was investigated in a meat model system for dry fermented sausages. In oxidised samples, increased protein carbonyl contents and decreased thiol concentrations were found. The initial concentration of protein carbonyls was significantly lower in oxidised samples at pH4.8 than in ones at pH5.2, but after ten days comparable levels were reached. The inhibition of proteolysis by the addition of a protease inhibitor cocktail did not influence protein oxidation. Yet, proteolysis was negatively affected by low pH values as well as by oxidation, resulting in a reduced release of amino acids during ripening.