EFFECT OF TREHALOSE ADDITION AND SUB-LETHAL HOMOGENIZATION ON RESISTANCE TO IN VITRO DIGESTION OF LACTOBACILLUS SALIVARIUS SPP. SALIVARIUS CECT 4063 IN DIFFERENT FOOD MATRICES AND PROCESSING CONDITIONS
Betoret N., Barrera C., Burca C., Seguí L., Garcia J., Hernández M.
Universitat Politecnica de Valencia, Spain
The consumption of fermented dairy foods is restricted in individuals with lactose intolerance and/or with high cholesterol levels, as well as in the population following vegetarian or vegan diets. This has encouraged the use in the last years of alternative food matrices for the delivery of probiotics, such as fruit and vegetable juices and cereal or legume-based products.
With regard to the unit operations involved in food processing, they are usually carried out under conditions that favor the loss of functionality in most probiotics. However, the addition of some specific ingredients, in particular trehalose, or the application of moderate processing conditions like sub-lethal high pressure homogenization (HPH) has been reported to increase the resistance of some probiotic strains to adverse conditions.
The aim of the present study was to evaluate the effect of trehalose addition (10% by weight) and sub-lethal homogenization (100 MPa) on plate count and resistance to in vitro digestion of Lactobacillus salivarius spp. salivarius CECT 4063 in different food matrices submitted to vacuum impregnation, air drying and freeze drying operations.
Lactobacillus salivarius spp. salivarius CECT 4063), supplied by the Spanish Culture Type Collection, was inoculated to commercial clementine juice. Food grade trehalose obtained from tapioca starch was added in 10% (w/w) to one third of the samples and another third was subjected to a homogenization pressure of 100MPa. Apple samples (var. Granny Smith) were vacuum impregnated with inoculated juices (trehalose added or not and homogenized or not) and after that air dried (40ºC) until dried samples reached a water activity of 0.35 or freeze dried (24 h).
Lactobacillus salivarius spp salivarius content in inoculated juices, vacuum impregnated, air dried and freeze dried samples, was estimated by the serial dilution and plating procedure. In order to evaluate the probiotics resistance to the intestinal and gastric juices, a modification of the protocol proposed by Charteris, Kelly, Morelli, & Collins (1998) for in vitro simulation of the gastrointestinal process was employed.
The results show that the survival to gastrointestinal digestion of Lactobacillus salivarius spp salivarius increases in mandarine juice and in vacuum impregnated apple. Additionally, the addition of 10% of trehalose improves the strain resistance when it is growth in mandarine juice. Considering the effect of air drying and freeze drying on plate count and strain resistance it can be observed a positive effect of sub-lethal homogenization pressure while trehalose addition resulted non favourable.
The effect of trehalose addition and sub-letal homogenization pressures in the survival to gastrointestinal digestion of Lactobacillus salivarius spp salivarius depends on the structure of food matrix considered more than its composition. The stain resistance to digestion when it is included in a solid fruit that has to be freeze dried, can be improved applying to the strain in the growth media, a moderate stress like a sub-lethal homogenization pressure.
Probiotics, Trehalose, Sub-lethal homogenization, Lactobacillus salivarius, Air drying, Freeze drying
Betoret N., et al. (2017). Effect of trehalose addition and sub-lethal homogenization on resistance to in vitro digestion of Lactobacillus salivarius spp. salivarius CECT 4063 in different food matrices and processing conditions.
Conference Proceedings of IPC2017. Paper presented at the International Scientific Conference on Probiotics and Prebiotics, Budapest (p. 16.). IPC2017