Centro de Investigación y Desarrollo en Criotecnología de Alimentos (CIDCA), CCT La Plata - CONICET-UNLP, 47 y 116, La Plata, Argentina.
Centro de Investigación y Desarrollo en Criotecnología de Alimentos (CIDCA), CCT La Plata - CONICET-UNLP, 47 y 116, La Plata, Argentina; Cátedra de Microbiología, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Calle 47 y 115, La Plata, Argentina.
Food Res Int. 2018 Oct;112:169-174. doi: 10.1016/j.foodres.2018.06.023. Epub 2018 Jun 15.
Spray drying was applied for the production of kefir powder. The survival of microorganisms after drying, storage and simulated gastrointestinal (GI) conditions was investigated. Kefir was obtained by fermentation of milk and whey permeate, and was dehydrated directly (traditional kefir) or using different carriers (skim milk, whey permeate and maltodextrin). Low survival (5.5 log and <2 log CFU/g for lactic acid bacteria and yeast respectively) of microorganisms was achieved when kefir was dehydrated without thermoprotectants (carriers). In contrast, survival of the microorganisms was significantly improved in the presence of different carriers. When skim milk (SM) was used as the carrier medium, lactic acid bacteria (LAB) survival was above 9 log CFU/g. In contrast, viability of yeast was dramatically reduced after spray drying in these conditions. When whey permeate was used as the carrier medium, LAB survival was 8 log CFU/g and yeast survival was above 4 log CFU/g. LAB in the kefir powder survived better the simulated GI conditions when spray drying was conducted in SM. LAB in kefir powder sample dehydrated in SM and SM plus maltodextrin remained stable for at least 60 days at 4 °C. Our results demonstrated that spray drying of kefir is a suitable approach to obtain a concentrated kefir-derived product.
喷雾干燥用于生产酸奶粉。研究了干燥后、储存期间以及模拟胃肠道（GI）条件下微生物的存活情况。酸乳是通过牛奶和乳清渗透物发酵获得的，并直接脱水（传统酸乳）或使用不同的载体（脱脂乳、乳清渗透物和麦芽糊精）进行脱水。当酸乳在没有热保护剂（载体）的情况下脱水时，微生物的存活率很低（乳酸菌和酵母分别为 5.5 log 和 <2 log CFU/g）。相比之下，在存在不同载体的情况下，微生物的存活率显著提高。当使用脱脂乳（SM）作为载体介质时，乳酸菌（LAB）的存活率超过 9 log CFU/g。相比之下，在这些条件下喷雾干燥后酵母的存活率急剧下降。当乳清渗透物用作载体介质时，LAB 的存活率为 8 log CFU/g，酵母的存活率超过 4 log CFU/g。在 SM 中进行喷雾干燥时，酸奶粉中的 LAB 更能耐受模拟 GI 条件。在 4°C 下，SM 干燥的酸奶粉和 SM 加麦芽糊精的 LAB 至少稳定 60 天。我们的结果表明，喷雾干燥酸乳是获得浓缩酸乳衍生产品的一种合适方法。
