The main subject of study is the effect the plant proteases bromelain and papain exert on turkey meat tenderness. Experiments are conducted with samples of raw meat in 3 different concentration levels of the enzyme solutions (50U/ml 100U/ml and 200 U/ml) and in 3 different time periods (duration) of treatment (24 h, 48 h, 72h). An increase in enzyme concentration and treatment duration results in a higher degree of protein hydrolysis in the turkey meat. The optimal conditions for hydrolysis with minimal loss of protein and highest retention of organoleptic qualities of the meat samples are established.

Pumpkin seed cake, a byproduct of cold-pressed oil production, represents a food waste material with a great potential for valorization. The objective of the present study is to optimize the papain enzymatic hydrolysis process of pumpkin seed cold-pressed oil cake (CPC) to obtain protein hydrolysates with the highest antioxidant activity. Box–Behnken Response Surface Methodology (RSM) was used to optimize the simultaneous effects of an enzyme concentration of papain, a temperature, and a reaction time on the process of enzymatic hydrolysis on pumpkin seed cold-pressed oil cake (CPC). For these three input factors, different values are used—1, 2, and 3% for papain concentration, 20, 30, and 40 °C for temperature, and 60, 120, and 180 min for hydrolysis time. Thus, the design generated a total of 21 experimental runs. The aim is to obtain protein hydrolysates with the highest antioxidant activity. The responses DPPH and ABTS were calculated and the determined regression models were statistically analyzed and validated. The results revealed that optimal conditions included a papain concentration of 1.0%, a temperature of 40 °C, and a hydrolysis time of 60 min to retrieve the highest level of bioactive compounds.

Hemp seed oil cake, a by-product of hemp seed oil extraction, is characterized by its high protein content and bioactive components, making it a valuable resource for the development of functional products through enzymatic hydrolysis. Hemp seed oil itself is renowned for its rich content of essential fatty acids, vitamins, and antioxidants, contributing to its widespread use in health and wellness products. Consequently, the residual cake presents significant potential for the food, pharmaceutical, and cosmetic industries as a source of high-quality protein ingredients. The optimization of enzymatic hydrolysis conditions is crucial for maximizing the efficiency and quality of the resulting protein hydrolysates. This study aims to optimize the hydrolysis process of hemp seed oil cake with bromelain, focusing on three key factors: enzyme concentration (E/S ratio), temperature, and time, to achieve hydrolysates with superior antioxidant activity. Response Surface Methodology (RSM) was applied using a Box–Behnken design to model and optimize the hydrolysis conditions. The experimental design involved three levels for each factor: 1%, 2%, and 3% for bromelain concentration; 20 °C, 30 °C, and 40 °C for temperature; and 60, 120, and 180 min for hydrolysis duration, resulting in 21 experimental runs. The antioxidant activity was assessed via DPPH and ABTS radical scavenging assays (%RSA), and the derived regression models were statistically analyzed and validated. The findings indicate that the optimal conditions for obtaining protein hydrolysates with the highest antioxidant activity are a bromelain concentration of 3.0%, a temperature of 40 °C, and a hydrolysis time of 60 min.

The purpose of this study is to assess the tenderizing effect of plant proteolytic enzymes upon raw rabbit meat. Tests are performed on rabbit meat samples treated with papain and two vegetal sources of natural proteases (extracts of kiwifruit and ginger root). Two variants of marinade solutions are prepared from each vegetable raw materials- 50% (w/w) and 100 % (w/w), with a duration of processing 2h, 24h, and 48h. Changes in the following physicochemical characteristics of meat have been observed: pH, water-holding capacity, cooking losses and quantity of free amino acids. Differences in values of these characteristics have been observed, both between control and test samples, as well as depending of treatment duration. For meat samples marinated with papain and ginger extracts, the water-holding capacity reached to 6.74 ? 0.04 % (papain), 5.58 ? 0.09 % (variant 1) and 6.80 ? 0.11 % (variant 2) after 48 hours treatment. In rabbit meat marinated with kiwifruit extracts, a significant increase in WHC was observed at 48 hours, 3.37 ? 0.07 (variant 3) and 6.84 ? 0.11 (variant 4). The test samples also have reduced cooking losses compared to control samples. In control samples, cooking loss is increased from 13.79% (2 h) to 20.78 % (48 h). SDS-PAGE of meat samples after 48 h of treatment shows a reduction in the intensity of actin and myosin bands in all variants with papain and vegetal extracts. Electrophoretic pattern of test samples depicts proteolysis and degradation of muscle proteins.

One of the innovative methods for real-time determination of food freshness is the application of pH-indicator sensors, where the color change can be used for the visual detection of acidic/basic volatile compounds formed during product storage due to microbial growth. The aim of the present study is to develop a pH-responsive freshness indicator based on anthocyanins from chokeberry (Aronia melanocarpa Elliot) and black carrot (Daucus carota ssp. sativus var. atrorubens Alef.), incorporated into an alginate/pectin/arabic gum composite film. The resulting films show distinct color changes as the pH varies. The color changes from red (pH 2.0 - 3.0) through pink and pale pink (pH 4.0, 5.0 and 6.0) to purple and blue (pH 7.0 - 8.0). The most distinct is the color transition between pH 6.0 and 7.0 for the black carrot extract and the chokeberry: black carrot mixture (1:3). The applicability of the developed pH-indicator films was demonstrated in chicken meat by tracking the changes during its storage at 4°C for 7 d. The observed results show a distinct color change from pink (day 1-3) to violet and blue on day 7. The developed pH- sensitive films have potential for use in a smart packaging system as a sensor for meat freshness monitoring.

The purpose of the present study was to develop edible composite films based on sodium alginate and pectin with incorporated Aronia melanocarpa (Michx.) Elliot and Thymus serpyllum L. extracts. The influence of the extracts on the physicochemical, optical, mechanical, and antioxidant properties of the films was investigated. The addition of the extracts changed the colour parameters and significantly increased the barrier properties to UV and visible light. This effect is more pronounced in the film with chokeberry extract and is due to the anthocyanins contained in it (75.43 μg cyd eq•g-1 , cyd eq-cyanidin equivalents). The antioxidant activity of films with incorporated extracts was 4-fold (thyme) to 7-fold (chokeberry) higher than the control alginate/pectin film. A significant improvement in the mechanical characteristics of the films with extracts was found. The values for tensile strength were 9.41 MPa (chokeberry) and 9.54 MPa (thyme), while for the film without extract-4.63 MPa. The resulting films could find potential application as active packaging with antioxidant properties, which could increase the quality and extend the shelf life of the foods packaged in them.