Manufacturing a functional low fat cheese using Taiwan ropy fermented milk (TRFM) and Lactococcus lactis subsp. cremoris T1 isolated from TRFM

• Main Authors: Yueh-Ling Hsieh, 謝月玲
• Other Authors: 陳明汝
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/92011250253755061461

碩士 === 臺灣大學 === 動物科學技術學研究所 === 98 === Fat reduction in cheese is associated with many textural and functional defects. Low-fat cheeses have low intensity of typical flavor and may develop a bitter off-flavor and hard, rubbery, dry and grainy texture. Exopolysaccharide (EPS) could increase the water-holding capacity and interfere with protein–protein interactions in food products, which are important properties required in fat replacement. In our previous study, EPS producing strain, Lactococcus lactis subsp. cremoris T1 (T1), was isolated from TRFM. This strain may act as a fat replacer in low fat cheese. Thus, the purpose of this study was to manufacture a new functional low fat cheese with TRFM、T1 and T4 strain and investigate the effects of TRFM、T1 and T4 (EPS-negative genetic variant, Lactococcus lactis subsp. cremoris T4, was isolated from TRFM) strain on the chemical, microbial, functional, physical and sensory characteristics of this low fat cheese. Skim milk was pasteurized at 65℃ for 30 min, inoculated with T1 strain/ T4 strain/ TRFM as starter cultures, and added rennet to form milk curd. The cheeses were then produced by cooked, cut and released whey from the milk curd. The full fat cheese and low fat cheese were positive and negative controls, respectively. The microbial analysis indicated that the cell counts of lactic acid bacteria in the low fat cheese samples inoculated with T1, T4 and TRFM were above 108 cfu/g. The low fat cheese inoculated with T1 and TRFM also showed a significantly higher moisture contents than the low fat cheese control. The moisture/protein ratios of the low fat cheese inoculated with T1 and fermented for 4 hrs (4-T1 sample) showed no significant differences with the ratio of the full fat cheese control. The further texture analysis verified that the 4-T1 and 8-T1 samples demonstrated a very similar texture profile to the full fat cheese control. In addition, the 8-T1 sample had the highest customer preferential scores in appearance, texture and flavor than other cheese samples. Additionally, the functional characteristics including antioxidation, antihypertension and immunoregulation were evaluated. The cheese samples made with TRFM、T1 and T4 have significantly higher ability of scavenging free radical than the control full-fat and low-fat cheeses during ripening period. The reactive oxygen species play an important role related to the degenerative or pathological processes of various serious diseases. This finding indicated that the cheese samples made with TRFM、T1 and T4 might possess natural antioxidants and compounds with radical scavenging activity. The cheeses made with T1、T4 and TRFM also showed a significantly higher inhibition in angiotensin-converting enzyme (ACE). ACE is known to associate with hypertension and congestive heart failure. ACE inhibitors in the TRFM、T1 and T4 samples may reduce the activity of the renin-angiotensin-aldosterone system. In conclusion, this study demonstrated that the low fat cheese made with TRFM and T1 not only gives a positive impact on the low fat cheese quality, but also provide the functions of a radical scavenging activity and ACE inhibition.