Survival and beneficial properties of lactic acid bacteria from raniculture subjected to freeze-drying and storage

Abstract

Aim: To evaluate the effect of freeze-drying and storage conditions on the viability and beneficial properties of lactic acid bacteria (LAB) for raniculture. Methods and Results: Lactococcus lactis CRL 1584, L. lactis CRL 1827, Lactococcus garvieae CRL 1828 and Lactobacillus plantarum CRL 1606 viability under different conditions was studied. 10% lactose and 5% skim milk + 5% lactose were excellent lyoprotectants, but 5% skim milk + 5% lactose and whey protein concentrated (WPC) or WPC + sugars were the lower cost lyoprotective options. The effect of temperature depended on both lyoprotectants and storage time. Thus, for Lactococcus, skim milk, skim milk + sucrose and WPC + sucrose were selected for lyophilization and storage at 4°C and skim milk + lactose for 25°C. For Lact. plantarum CRL 1606, the best lyoprotectants for lyophilization and storage at 4°C were milk + sugars and WPS + sucrose and, at 25°C, skim milk + sucrose. Conclusions: Lactic acid bacteria viability after freeze-drying was strainspecific and depended on the lyoprotectant used. Highest viability was obtained when stored at 4°C, and the beneficial properties remained stable for 18 months independently of storage temperature. Significance and Impact of the Study: The studies reported for the first time in this work are of primary interest to obtain dried bacteria to be included in beneficial products for raniculture.

Plants and Lactic Acid Bacteria Combination for New Antimicrobial and Antioxidant Properties Product Development in a Sustainable Manner

“…This process can lead to the destruction of bacterial membranes and cause harmful damage [64]. Moreover, during lyophilisation, the removal of water by sublimation additionally increases osmotic pressure and can be harmful for membranes and surface proteins [65]. For this reason, cryprotectants are usually added to maintain the viability of microorganisms [64].…”

“…For this reason, cryprotectants are usually added to maintain the viability of microorganisms [64]. Different polymers, sugars, milk, honey, polyols, and amino acids have been tested for their protective effect during lyophilisation [64][65][66]. Disaccharides, such as maltose, sucrose, and trehalose, are able to induce shrinkage of the cells by osmosis-derived dehydration before freezing, thereby reducing intracellular ice formation [64].…”

Improvement of a dry formulation ofPseudomonas fluorescensEPS62e for fire blight disease biocontrol by combination of culture osmoadaptation with a freeze-drying lyoprotectant

“…; Montel Mendoza et al . ). The growth medium used for culture the micro‐organism is also a critical parameter, and several factors like the presence of compatible solutes can promote survival of bacteria throughout dehydration and storage in the dried state (Carvalho et al .…”

Storage stability of freeze-dried Lactobacillus plantarum S20 starter culture as affected by various formulations of drying medium, and its fermentation characteristics in mung bean (Vigna radiata L.) slurry was studied by Sulabo et al.

“…Thus, selecting appropriate drying medium as a protective matrix can produce a stable final formulation of freeze-dried cell culture with minimal viability loss. Several studies have investigated the use of various protective agents during feeze-drying consisting of additives (Carvalho et al, 2002), disaccharides, and skim milk (Carvalho et al, 2003b;Jalali et al, 2012;Mendoza et al, 2013;Gisela et al, 2014;Jofré et al, 2015) in order to minimize viability loss of LAB during cryopreservation. In addition, drying media also serve as carriers of freezedried starter cultures for fermentation applications.…”