Sesame water-soluble proteins fraction contains endopeptidases and exopeptidases with high activity: A natural source for plant proteases

Upcycling of Defatted Sesame Seed Meal via Protein Amyloid-Based Nanostructures: Preparation, Characterization, and Functional and Antioxidant Attributes

Herein, the possibility of valorizing defatted sesame seed meal (DSSM) as a viable source for valuable plant proteins and amyloid-based nanostructure was investigated. Sesame seed protein isolate (SSPI) and the major storage protein globulin (SSG) were prepared by alkaline extraction-isoelectric point precipitation as well as fractionation in the case of SSG. The protein samples were characterized for their physicochemical attributes. SSPI and SSG were also evaluated for their ability to form amyloid structures under heating (90 °C) at low pH (2.0). Additionally, the functional attributes, antioxidant activity, and biocompatibility of the proteins and amyloid nanostructures were also examined. SSPI and SSG were both successfully prepared from DSSM. The data showed that the physicochemical attributes of both protein samples were quite similar, except for the fact that SSG was mostly composed of 11S globulin, as evinced by Tricine-SDS-PAGE analysis. TEM micrographs revealed that SSG was able to form curly-shaped fibrillar amyloid structures, whereas those derived from SSPI were mostly amorphous. Thioflavin-T assay and Tricine-SDS-PAGE analysis indicated that acidic heating promoted protein hydrolysis and self-aggregation of the hydrolyzed peptides into a β-sheet rich amyloid structure. Importantly, the amyloid preparations displayed commendable solubility, superior water and oil holding capacities, and antioxidant activity against DPPH and ABTS. The protein amyloid nanostructures were found to be non-toxic against RAW264.7 cells, HaCaT cells, and red blood cells. These findings indicate that DSSM could be upcycled into valuable protein amyloid structures with good potentialities as novel food ingredients.

Unraveling the biological potential of chicken viscera proteins: a study based on their enzymatic hydrolysis to obtain hydrolysates with antioxidant properties

Chicken meat production has increased over the years, leading to a proportional increase in waste generation, which often contains high levels of proteins, such as viscera. Therefore, this study aimed to investigate the enzymatic hydrolysis of chicken viscera proteins as a strategy to value solid waste from the poultry industry. The hydrolysates were characterized for their antioxidant properties and molecular weight distribution. Additionally, the enzymatic hydrolysis process was scaled up from 125 mL flasks with 50 mL of protein solution to 3 L using a 6 L bioreactor. The enzymatic hydrolysis of chicken viscera proteins using a binary mixture of proteases (85.25 U/mL of each enzyme, Alcalase and Flavourzyme, totaling 170.5 U/mL) resulted in an increase of up to 245% in 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging, 353% 2,2-diphenyl-1-picryl-hydrazyl (DPPH) in radical scavenging, 69% in Ferric Reducing Antioxidant Power Assay (FRAP) and 146% in total reducing capacity (TRC). The antioxidant properties of the protein hydrolysates are preserved during the scale-up of enzymatic hydrolysis. Protein fractions smaller than 5 kDa showed the highest ABTS and DPPH radical scavenging activities, while fractions greater than 30 kDa showed the best results for the FRAP method.

Metagenomic insights into protein degradation mechanisms in natural fermentation of cassava leaves

Cassava (Manihot esculenta Crantz) leaves, the primary by-product of cassava processing, constitute a significant protein source, accounting for 18 to 38 percent on a dry weight basis. Despite their nutritional value, a substantial portion of these leaves is often discarded post-harvest, resulting in notable resource waste. This study employs metagenomic technology to investigate the protein degradation mechanism in cassava leaves, aiming to provide a technical reference for value-added of this by-product. Following a 36-hour period of natural fermentation, the protein degradation rate reached 58%, a phenomenon intricately linked to both the microbial community structure and its functional properties. Notably, Lactococcus and Enterobacter, recognized for their abundant protease activity, were predominant. Metagenomically assembled genomes further revealed Lactococcus's substantial role in producing flavors and active compounds, including amino acids and peptides. This study offers novel perspectives to the foodization and high-value utilization of cassava by-products, emphasizing the sustainable exploitation of biomass resources.

Strawberry Protease as a Laundry Detergent Additive Candidate: Immobilization, Compatibility Study with Detergent Ingredients, and Washing Performance Test

The potential of strawberry-derived protease as a component of laundry detergent is investigated. The compatibility of the enzyme with various surfactants, oxidizing agents, and commercial detergents is tested. The immobilized enzyme prepared by immobilizing Co2+ ions together with the enzyme is also tested. Strawberry crude protease shows high stability in the presence of surfactants frequently used in detergents. The enzyme is found to be relatively stable to oxidizing agents. In addition, it is determined that strawberry protease works in excellent compatibility with different commercial solid and liquid detergents in the Turkish market and also maintains its stability very well. Washing tests based on visual examination also reveal that the enzyme improves the washing performance of the tested detergent. All these properties and high activity at alkaline pH make this enzyme a very strong candidate for use in laundry detergent formulations.

Preparation and investigation of novel endopeptidase-exopeptidase co-immobilized nanoflowers with improved cascade hydrolysis

Enzymatic hydrolysis is a promising approach for protein and food processing. However, the efficiency of this approach is constrained by the self-hydrolysis, self-agglomeration of free enzymes and the limited applicability resulted from enzymes' selectivityt. Here, novel organic-inorganic hybrid nanoflowers (AY-10@AXH-HNFs) were prepared by coordinating Cu2+ with both endopeptidase of PROTIN SD-AY10 and exopeptidase of Prote AXH. The results indicate that the AY-10@AXH-HNFs exhibited 4.1 and 9.6 times higher catalytic activity than free Prote AXH and PROTIN SD-AY10, respectively, for the enzymatic hydrolysis of N-benzoyl-L-arginine ethyl ester (BAEE). The kinetic parameters of Km, Vmax and Kcat/Km by AY-10@AXH-HNFs were determined to be 0.6 mg/mL, 6.8 mL·min/mg and 6.1 mL/(min·mg), respectively, surpassing the values obtained from free endopeptidase and exopeptidase. Furthermore, the ability of AY-10@AXH-HNFs to retain 41 % of their initial catalytic activity after undergoing 5 cycles of repeated use confirmed their stability and reusability. This study introduces a novel approach of co-immobilizing endopeptidase and exopeptidase on nanoflowers, resulting in significantly enhanced stability and reusability of the protease in catalytic applications.

Amino Acid Profiling and SDS-PAGE Analysis of Protein Isolates Obtained from Nonconventional Sources

Proteins play an imperative role in enhancing the nutritional status of the human body. The present study was designed to determine the molecular weight of protein isolates prepared from defatted oilseeds, i.e., sesame, flaxseed, and canola, using SDS-PAGE. The electropherogram revealed protein bands ranging from 15 to 65 kDa. Furthermore, proteins were subjected to amino acid profiling followed by calculation of amino acid score with reference to requirement for preschool children. The amino acid profiling results indicated that sesame protein isolates (SPI) exhibited the highest values for aromatic amino acids, histidine, isoleucine, and valine. However, the maximum values for sulfur-containing amino acids were depicted by flaxseed protein isolates (FPI). Moreover, the lysine content was highest in canola protein isolates (CPI). Results indicated better profile and quality of proteins, capable to meet the requirements of essential amino acids, especially for preschoolers. Moreover, the values for the protein digestibility corrected amino acid score (PDCAAS) and in vitro protein digestibility (IVPD) were also determined. Conclusively, protein isolates from defatted oilseeds exhibit better-quality proteins with a balanced amino acid profile. By potential utilization in numerous food products, these proteins can play a pivotal role in fulfilling the nutritional requirements of individuals, especially in developing economies.

Oilseed Extracts from Local Markets as Promising Coagulant Agents for Milk from Various Mammalian Species

The aim of this study was to identify novel milk coagulants to be used in cheesemaking. For this purpose, aqueous extracts from safflower (Carthamus tinctorius), sunflower (Helianthus annuus), flax (Linum usitatissimum) and sesame (Sesamum indicum) seeds were tested for their caseinolytic (CA) and milk coagulating properties (MCA) in skim milk at temperatures of 25, 37, 50, 65 and 80 °C. The seed oil samples with the highest temperature ranges in regard to coagulation efficiency were then tested in cow, buffalo, goat and sheep milks and the MCA and curd yield (CY) parameters were measured at different temperatures. Due to their high milk coagulation efficiency (CE) in all types of milk and at different temperatures, the sesame and sunflower seed extracts proved to be particularly interesting and their CY parameters were similar to those obtained with animal rennet. Moreover, our results confirm that oilseed coagulants are capable of coagulating milk and can also be considered as potential animal rennet substitutes. This study provides valuable insights into the development of potential vegetable coagulants that could be used for various production processes aimed at specific target consumers.