Enhancement of ethanol production efficiency in repeated-batch fermentation from sweet sorghum stem juice: effect of initial sugar, nitrogen and aeration

BACKGROUND: Ethanol concentration (PE), ethanol productivity (QP) and sugar consumption (SC) are important values in industrial ethanol production. In this study, initial sugar and nitrogen (urea) concentrations in sweet sorghum stem juice (SSJ) were optimized for high PE (≥10%, v/v), QP, (≥2.5 g/L·h) and SC (≥90%) by Saccharomyces cerevisiae SSJKKU01. Then, repeated-batch fermentations under normal gravity (NG) and high gravity (HG) conditions were studied. RESULTS: The initial sugar at 208 g/L and urea at 2.75 g/L were the optimum values to meet the criteria. At the initial yeast cell concentration of ~1 × 108 cells/mL, the PE, QP and SC were 97.06 g/L, 3.24 g/L·h and 95.43%, respectively. Repeated-batch fermentations showed that the ethanol production efficiency of eight successive cycles with and without aeration were not significantly different when the initial sugar of cycles 2 to 8 was under NG conditions (~140 g/L). Positive effects of aeration were observed when the initial sugar from cycle 2 was under HG conditions (180­200 g/L). The PE and QP under no aeration were consecutively lower from cycle 1 to cycle 6. Additionally, aeration affected ergosterol formation in yeast cell membrane at high ethanol concentrations, whereas trehalose content under all conditions was not different. CONCLUSION: Initial sugar, sufficient nitrogen and appropriated aeration are necessary for promoting yeast growth and ethanol fermentation. The SSJ was successfully used as an ethanol production medium for a high level of ethanol production. Aeration was not essential for repeated-batch fermentation under NG conditions, but it was beneficial under HG conditions.

Sugar intake and metabolic syndrome among older adults in Peninsular Malaysia

@#Introduction: Sugar is widely consumed and excessive intake has been associated with increased risk of weight gain, diabetes mellitus and cardiovascular diseases, leading to metabolic syndrome (MetSyn). However, the association between sugar intake and MetSyn has seldom been studied among multi-ethnic Malaysian older adults. Methods: A total of 1,057 respondents aged ≥60 years were recruited through multistage random sampling from selected states. Anthropometric parameters, blood pressure, blood test for sugar and lipid profile were determined. Dietary intake was derived using a 7-day dietary history questionnaire (DHQ) and a semi-quantitative food frequency questionnaire (FFQ) for added sugar intake. Results: Prevalence of MetSyn was 39.9%, 30.9% and 42.2% using the harmonised definition, International Diabetes Federation (IDF) and National Cholesterol Education Program’s Adult Treatment Panel III (NCEP-ATPIII) definitions respectively. Mean total sugar intake was 40.5±32.0 g (8 tsp) and added sugar intake was 33.0±31.0 g (6 tsp). Excessive added sugar consumption at 100th percentile increased risks of high total cholesterol by two-fold (p<0.001) and triglyceride by 1.8 fold (p<0.001). Total sugar intake at 50th percentile increased risk of high blood pressure by 0.68 fold (p<0.05) and total sugar intake at 50th, 75th and 100th percentile increased total cholesterol risk by 1.7 fold (p<0.01), 1.5 fold (p<0.05) and 2.3 fold (p<0.001) respectively. Conclusion: Excessive sugar consumption among older adults showed no association with MetSyn but revealed significant associations with blood pressure and lipid profiles. Effects of long term excessive consumption of sugar on health outcomes in older persons should be investigated.

The awareness level and needs for education on reducing sugar consumption among mothers with preschool children

BACKGROUND/OBJECTIVES: The purpose of this study was to find out the level of knowledge on sugar-related nutrition among mothers with preschool children. SUBJECTS/METHODS: The study conducted a survey on 350 mothers whose children attended daycare. The dietary lives of the children and the nutritional knowledge of the mothers on sugar were checked. In order to analyze results, SPSS 18.0 was used. ANOVA and t-test were also performed to analyze recognition and educational needs. RESULTS: When the degree of nutritional knowledge was measured and analyzed, the results showed about 11 average points out of 15. The higher a group's nutritional knowledge, the better the dietary habits and activities were and the activities were more ccommon. The group with a low level of nutritional knowledge consumed more foods with high sugar content, but this difference was not statistically significant. Also the children from the group of mothers that provided nutritional education to their children were more likely to engage in better dietary habits and activities. CONCLUSIONS: 66.5% respondents did not know about policies to reduce sugar consumption, but most indicated that education on reducing sugar consumption is needed. Therefore, a government-driven search for efficient methods to campaign and publicize sugar reduction is needed in order to continuously provide appropriate education.

Correlation between attention deficit hyperactivity disorder and sugar consumption, quality of diet, and dietary behavior in school children

This study investigated the correlation between consumption of sugar intake by fifth grade students in primary schools and development of Attention Deficit Hyperactivity Disorder (ADHD). A total of 107 students participated, and eight boys and one girl (8.4% of the total) categorized as high risk for ADHD according to diagnostic criteria. There were significant differences in the occupations and drinking habits of the respondents' fathers between the normal group and risk group. In a comparison of students' nutrition intake status with daily nutrition intake standards for Koreans, students consumed twice as much protein as the recommended level, whereas their calcium intake was only 60% of the recommended DRI (dietary reference intake). Regarding intake volume of vitamin C, the normal group posted 143.9% of the recommended DRI, whereas the risk group showed only 65.5% of the recommended DRI. In terms of simple sugar intake from snacks, students in the normal group consumed 58.4 g while the risk group consumed 50.2 g. These levels constituted 12.5% of their total daily volume of sugar intake from snacks, which is higher than the 10% standard recommended by the WHO. In conclusion, children who consumed less sugar from fruit snacks or whose vitamin C intake was less than RI was at increased risks for ADHD (P < 0.05). However, no significant association was observed between total volume of simple sugar intake from snacks and ADHD development.