Katechaki Eleftheria, Panas Panayiotis, Rapti Katerina, Kandilogiannakis Leonidas, Koutinas Athanasios A
Food Biotechnology Group, Section of Analytical Environmental and Applied Chemistry, Department of Chemistry, University of Patras, GR-26500 Patras, Greece.
J Agric Food Chem. 2008 Jul 9;56(13):5316-23. doi: 10.1021/jf703585y. Epub 2008 Jun 10.
This study provides a contribution to hard-type cheese starter culture production through the use of a freeze-dried culture in the ripening of hard-type cheeses. The effect of initial cell concentration, ripening temperature, and cell immobilization of kefir on the degree of openness, mold spoilage, microbial associations, physicochemical characteristics, and aroma-related compounds was studied. Use of kefir starter cultures resulted in cheese with an increased shelf life and resistance to spoilage as compared to control cheeses without kefir inoculants. Furthermore, the freeze-dried kefir culture improved aroma, taste, and texture characteristics while increasing the degree of openness in comparison to traditional hard-type cheese products. The kefir culture resulted in an increase in counts of total aerobic bacteria, yeasts and molds, lactococci, and lactobacilli until the 15th day of ripening. From then on, only lactobacilli counts increased, reaching levels up to 9.17 log CFU/g in cheeses ripened at 5 degrees C using freeze-dried kefir cells immobilized on casein. SPME-GC/MS analysis revealed major differences in volatile composition, especially with regard to alcohols (up to 75%), carbonyl compounds (up to 75%), and esters (up to 64%) between cheeses made with kefir cells and cheeses made without kefir inoculants.
本研究通过在硬质奶酪成熟过程中使用冻干培养物，为硬质奶酪发酵剂培养物的生产做出了贡献。研究了开菲尔初始细胞浓度、成熟温度和细胞固定化对硬质奶酪的开放程度、霉菌腐败、微生物群落、理化特性以及与香气相关化合物的影响。与未接种开菲尔的对照奶酪相比，使用开菲尔发酵剂培养物可使奶酪的保质期延长且更耐腐败。此外，与传统硬质奶酪产品相比，冻干开菲尔培养物改善了奶酪的香气、口感和质地特性，同时增加了开放程度。在成熟的第15天之前，开菲尔培养物使需氧菌总数、酵母和霉菌、乳球菌和乳酸菌的数量增加。从那时起，只有乳酸菌数量增加，在使用固定在酪蛋白上的冻干开菲尔细胞于5℃成熟的奶酪中，乳酸菌数量达到高达9.17 log CFU/g的水平。固相微萃取-气相色谱/质谱分析显示，使用开菲尔细胞制成的奶酪与未接种开菲尔的奶酪在挥发性成分上存在主要差异，尤其是在醇类（高达75%）、羰基化合物（高达75%）和酯类（高达64%）方面。
