Development of a functional fermented milk with L-carnitine using sequential quadratic programming
Date Issued
2007
Date
2007
Author(s)
Chen, Jen-Yuan
DOI
zh-TW
Abstract
The objective of this research was to create a new synbiotic fermented milk with high L-carnitine and healthy benefits. The final aim was to increase the variety and choice of dairy products. In this study, skim milk was mixed with prebiotics (fructooligosaccharides, FOS and isomaltooligosaccharides, IMO) and whey protein concentrate. The mixture was then inoculated with probiotics (Lc. lactis subsp. cremoris, Lc. lactis subsp. lactis, and Lb. rhamnosus) and fermented at 37 ℃ for 7 hr. Moreover, the proportion of the prebiotics and whey protein concentrate was optimized using response surface methodology (RSM) to construct a surface model, with sequential quadratic programming (SQP) subsequently adopted to optimize the model and the processing conditions.
Optimization results demonstrated that addition of prebiotics increased the level of L-carnitine and lactic acid bacteria (LAB) counts in fermented milk with 1.0 % FOS and 3 % IMO. The verification experiment yielded a result close to the predicted values, with no significant difference（P＞0.05）. The components of the functional fermented milk were 87.36 % moisture, 3.59 % CP, 0.08 % fat, 8.24 % carbohydrate and 0.73% ash. And the pH value and titratable acidity was 6.34 and 0.23%, respectively. Although the sensory evaluation results indicated that the consumers, giving a score above 6.0, could accept this product, additional sweeteners and flavors might be needed for possible commercialization of this product. The storage results showed that LAB counts remained above 107 CFU/mL for samples stored for one month. On contrast, L-carnitine contents dropped during storage. And the standard plate counts were very close to LAB counts with no coliform bacteria, it indicated that there were no other microorganisms grew in the functional fermented milk during storage. Because the post acidification happened during storage, pH value dropped and titratable acidity increased.
Subjects
左旋肉生僉
果寡醣
異麥芽寡醣
反應曲面法
序列二次規劃法
L-carnitine
fructooligosaccharides
isomaltooligosaccharides
response surface methodology
sequential quadratic programming
Type
thesis
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