Department of Biologia e Chimica Agro-Forestale ed Ambientale, University of Bari, via Amendola 165/a, 70126 Bari, Italy.
Food Microbiol. 2011 Aug;28(5):1062-71. doi: 10.1016/j.fm.2011.02.011. Epub 2011 Mar 2.
Weissella cibaria, Lactobacillus plantarum, Lactobacillus sp. and Lactobacillus pentosus were variously identified from blackberries, prunes, kiwifruits, papaya and fennels by partial 16S rRNA gene sequence. Representative isolates from each plant species were screened based on the kinetics of growth on fruit juices. A protocol for processing and storage of red and green smoothies (RS and GS) was set up, which included fermentation by selected lactic acid bacteria starters and exo-polysaccharide producing strains. Starters grew and remained viable at ca. 9.0 log cfu g(-1) during 30 days of storage at 4 °C. No contaminating Enterobacteriaceae and yeast were found throughout storage. Values of soluble solids, total titratable acidity and viscosity distinguished started RS and GS compared to spontaneously (unstarted) fermented smoothies. Color difference dE∗(ab) and browning index were positively affected by lactic acid fermentation. Consumption of carbohydrates by lactic acid bacteria was limited as well as it was the lactic fermentation. Consumption of malic acid was evident throughout storage. Polyphenolic compounds and, especially, ascorbic acid were better preserved in started RS and GS compared to unstarted samples. This reflected on the free radical scavenging activity. A statistical correlation was only found between the level of ascorbic acid and free radical scavenging activity. As shown by a first-order equation, the rate of degradation of ascorbic acid through storage were found to be higher in the unstarted compared to started RS and GS. Fermentation by lactic acid bacteria clearly improved the sensory attributes of RS and GS.
通过部分 16S rRNA 基因序列，从黑莓、李子、猕猴桃、木瓜和茴香中鉴定出 Weissella cibaria、植物乳杆菌、乳杆菌属和戊糖乳杆菌。根据果汁生长动力学，从每种植物物种中筛选出代表性分离株。建立了红、绿冰沙（RS 和 GS）的加工和储存方案，其中包括选择的乳酸菌启动子和外多糖产生菌株的发酵。启动子在 4°C 下储存 30 天时可生长并保持约 9.0 log cfu g(-1)的活力。在整个储存过程中未发现肠杆菌科和酵母污染。与自发（未启动）发酵的冰沙相比，可溶性固形物、总可滴定酸度和粘度值可区分启动的 RS 和 GS。颜色差异 dE∗(ab)和褐变指数受乳酸发酵的积极影响。乳酸菌对碳水化合物的消耗以及乳酸发酵受到限制。在整个储存过程中都能明显消耗苹果酸。与未启动的样品相比，启动的 RS 和 GS 中多酚化合物，尤其是抗坏血酸得到更好的保存。这反映在自由基清除活性上。仅在抗坏血酸水平和自由基清除活性之间发现了统计相关性。通过一级方程表明，与启动的 RS 和 GS 相比，未启动的 RS 和 GS 中抗坏血酸通过储存的降解速度更高。乳酸菌发酵明显改善了 RS 和 GS 的感官属性。
