Effect of Microbial Enzymes on the Changes in the Composition and Microstructure of Hydrolysates from Poultry By-Products

Svetlana Merenkova,Oksana Zinina,Alexander Kuznetsov,Tatyana Shnyakina,Irina Lykasova

doi:10.3390/fermentation7030190

Svetlana Merenkova, Oksana Zinina + Show 3 more

Open Access

https://doi.org/10.3390/fermentation7030190

Copy DOI

Abstract

Poultry by-products are promising for the production of protein hydrolysates by enzymatic hydrolysis. The aim of the study is to research the effect of bacterial concentrates on the changes in the amino acid composition and microstructure of poultry by-products during fermentation. Hydrolysis of the gizzards and combs was carried out with a liquid concentrate of bifidobacteria and propionic acid bacteria. As a result of microstructural study of fermented by-products, a decrease in the perception of histological dyes, poor visualization of the cell elements and blurring of the connective tissue matrix were established. During morphometric analyses, we found a reduction in the specific area of connective tissue, the diameter of collagen fibers and the thickness of muscle fibers. A significant effect of the fermentation on the particle size distribution was noted; samples hydrolyzed by microbial enzymes were characterized by a high uniformity of particle sizes and a large number of small particles. Our research revealed an increase in the concentration of free amino acids in the hydrolysates during the fermentation period. The results of biochemical and microscopic analysis confirm the good hydrolysability of hen combs and gizzards under the action of microbial enzymes.

Highlights

Published: 12 September 2021Fermentation is a biotechnological process that results in the splitting of complex organic molecules under the action of enzymes into simpler ones
In control samples of hen gizzards not subjected to fermentation, microsections are represented by fragments of the muscle layer with small areas of the mucous membrane (Figure 1(A1))
Our results proved that the proteolytic enzymes of the selected microorganisms are able to catalyze the hydrolysis of connective tissue, but less effectively than muscle tissue

Summary

Introduction

Fermentation is a biotechnological process that results in the splitting of complex organic molecules under the action of enzymes into simpler ones. The fermentation processes of food systems are used to purposefully change the nutritional and biochemical characteristics. To ensure effective fermentation of raw materials, it is necessary to take into account the specifics of the substrate for certain types of microorganisms, particular environmental conditions (humidity, temperature, pH), the availability of nutrients and oxygen, the presence of competitive microorganisms and the duration of the process [4]. Fermented food systems are complex biosystems that include both their own raw material enzymes and enzymes produced by microorganisms as a result of their metabolic activity. Fermenting microorganisms provide structural and biochemical changes in the collagen of raw materials, increasing the bioavailability of the protein [5]. It is established that under the action of biological substances, proteolysis occurs, in which protein molecules

Objectives

Methods

Results

Conclusion