Viabilidade de Lactobacillus acidophilus livre e microencapsulado em sucos funcionais

Abstract

The increased interest and consumption of functional foods, especially those containing probiotic microorganisms, is due to the awareness of the importance that food has on health. However, most of these products are of dairy origin, resulting in an impediment to consumption by the population, such as lactose intolerant, milk protein allergic and hypercholesterolemic. From this problem, fruit juices appear as promising vehicles for probiotic crops. The microencapsulation technique contributes to increase the survival of microorganisms by forming a physical barrier against unfavorable conditions. Thus, the present study aims to elaborate functional beverages from commercial orange, grape and lemonade juices added with Lactobacillus acidophilus, free or microencapsulated by spray drying method using soybean and maltodextrin as wall material. The control fruit juices with free and microencapsulated probiotic cells were stored under refrigeration at 8 ° C for 28 days. The drinks had their centesimal composition detailed on the 7th day of storage. In vitro gastrointestinal (SGI) simulations were performed at the beginning and end of storage to assess cell survival rate. The juice that presented the best results regarding viability during the shelf life and survival of the in vitro digestibility system was submitted to sensory, microbiological, rheological and color analysis. After 28 days of storage, the beverages containing microcapsules and L. acidophilus free cells were 6.72 and 3.03 log CFU.mL-1 viable. respectively in orange juice and 6.18 and 2.28 log UFC.mL-1 respectively in grape juice. Lemonade showed no viable cells on day 28 for any of the treatments analyzed. During SGI, L. acidophilus free in fruit juices lost an average of 3.06 log cycles of viability, while encapsulated cells showed resistance, reducing 1.24 log UFC.mL-1 after in vitro gastrointestinal simulation on day 1. of storage. At the end of storage, the free probiotic lost all viability, while the microencapsulated showed a reduction of 1.74 log CFU.mL-1 in orange and grape juices, while the lemonade did not show viable cells. Despite the physicochemical changes and the centesimal composition of the added juices of free and microencapsulated L. acidophilus, these were not sensorially noticeable. The results of the microbiological and physicochemical analyzes were within the normal parameters required by current legislation, qualifying the products as fit for consumption. All of the orange juice formulations had an acceptance higher than 70% and the average of the analyzed attributes (appearance, consistency, texture, color, taste, aroma and overall evaluation) did not differ for any of the three treatments, as well as the values. found by color and viscosity analysis. Regarding purchase intent, over 60% of tasters would buy the samples evaluated. It was concluded that orange and grape juices were considered promising vehicles of probiotic cultures, especially when microencapsulated.