Probiotic Potential and Technological Properties of Bacteriocinogenic Lactococcus lactis Subsp. Lactis UTNGt28 from a Native Amazonian Fruit as a Yogurt Starter Culture.

Gabriela N Tenea,Jimena Suárez

doi:10.3390/microorganisms8050733

Abstract

A native Lactococcus lactis subsp. lactis UTNGt28 (GenBank accession no: MG675576.1) isolated from Amazonian fruit of the tropical Caimitillo (Chrysophyllum oliviforme) tree and the commercial strain Lactococcus lactis subsp lactis ATCC11454 (LacAT) were targeted ex vitro in whole milk in combination with Streptococcus thermophilus ATCC19258 to obtain a fermented probiotic beverage. Concomitant with cell viability determination during storage (28 days), the pH, titratable acidity, syneresis, protein and fat were evaluated. The results indicated that neither UTNGt28 nor LacAT displayed a high capacity to ferment whole milk and survive during storage; a statistically significant difference (p < 0.05) in cell viability was registered for UTNGt28 compared with LacAT when inoculated alone or in combination with S. thermophilus. A principal component analysis showed a clear difference between the yogurt formulations at day 1 and 28 of storage. The PC 1 explained 46.8% of the total variance (day 28), was loaded in the negative (−) direction with titratable acidity (% lactic acid), while the PC 2 explained 22.5% (day 1) with pH. PC 1 was loaded in the positive (+) direction with pH, cell viability, syneresis, fat and protein. Overall results indicated that UTNGt28 has the technological properties for further development of a new probiotic product.

Highlights

Lactic acid bacteria (LAB) have been used for food production, as they improve flavor, aroma and texture characteristics, complying with consumer needs
Milk is a suitable environment for growing lactic acid bacteria, it is important to evaluate its properties considering that the new candidate, UTNGt28 strain, was isolated from a fruit microenvironment
The viability of probiotic bacteria in the new yogurt formulations depends upon the strain type and culture mixture ratio

Summary

Introduction

Lactic acid bacteria (LAB) have been used for food production, as they improve flavor, aroma and texture characteristics, complying with consumer needs. LAB strains as a starter culture produce metabolites with an overall inhibitory capacity, contributing to the extension of the shelf life of food products [1]. The starter bacteria Streptococcus thermophilus is known for its use in the production of yogurt, as it is the only species from its genera recognized as Generally Recognized As Safe (GRAS) by the Federation of Drug Administration [5,6]. Its fundamental function during milk fermentation is the rapid conversion of lactose into lactic acid, preventing the growth of pathogens in the fermented product [9]. Due to its proteolytic activity and the conversion of amino acids, it contributes to the final texture (moisture, softness) and taste of dairy products

Methods

Results

Conclusion