Stirred Yoghurts Fortified with Colostrum-Influence of Colostrum Addition on its Acidification Process and Rheological Properties

Adriana Bomba,Maciej Kotowski,Krzysztof Borawski,Andrzej Babuchowski

doi:10.15344/2456-8171/2019/144

Abstract

The antimicrobial and immunostimulatory properties of colostrum have been known and valued for a long time. Due to the beneficial influence on health, colostrum was considered to be a nutraceutical. The aim of this research was to investigate the influence of colostrum addition (one was defatted and spray dried and the other was only lyophilized) on a kinetics of microbial acidification of milk and on quality of the final product. To this end, four different technological variants of yoghurts were produced accounting for different moment of colostrum addition (before and after incubation), as well as the amount of colostrum introduced (0.5% and 1%). Acidification rate increased with colostrum addition. Colostrum did not inhibit a growth of St. thermophilus and L. bulgaricus. Addition of colostrum which was defatted and spray dried lifted diauxic growth of yoghurt culture due to delivery of high amount easily hydrolysed (unfolded) proteins. Yoghurts with lyophilized colostrum had higher content of myristic (C14:0), pentadecanoic (C15:0), palmitic (C16:0), margarine (C17:0), heptadecanoic (C17:1), stearic (C18:0), oleic (cis) (C18:1Δc), linoleic (C18:2) and conjugated linoleic acids (C18:2 CLA). What is more, colostrum addition accounted for smaller gel particles in prepared yoghurts. Rheological analysis of yoghurts fortified with lyophilized colostrum revealed that there was a slight increase in apparent viscosity within a range of shear stress up to 101/s. It was found that 1% of colostrum addition assured better water biding capacity of yoghurts. All yoghurts remained stable under storage at 4˚C for 28 days.

Highlights

Yoghurt productionColostrum bovinum is and early milk of cows which differs in its composition in comparison to the mature milk
Colostrigen had higher fat, and lower protein content than Colostrum Max (Table 2), which was a consequence of their preparation (Colostrum Max was defatted before dehydration)
Analysing the course of acidification curves (Figure 1) of control samples with samples A (0.5% colostrum addition before incubation) and B (1% colostrum addition before incubation), it can be concluded that the addition of colostrum did not inhibit the growth of yogurt bacteria, but accelerated acidification kinetics of milk-inoculated with yoghurt culture

Summary

Introduction

Colostrum bovinum is and early milk of cows which differs in its composition in comparison to the mature milk. It possesses all of the substances needed for a proper development of a newborn. It is rich in protein, fat, as well as oligosaccharides and micronutrients. It contains lactoferrin, lysozyme and immunoglobulins that have immunostimulatory function [1‎‎,2]. Due to growth factors colostrum stimulates the muscle development and decreases recovery time [‎4]. For the above mentioned reasons, colostrum fortification brings new possibilities to create functional food products

Objectives

Methods

Results

Conclusion