Preparation, characterization, and antimicrobial activity of nanoemulsions incorporating citral essential oil.

Citral is a typical essential oil used in the food, cosmetic, and drug industries and has shown antimicrobial activity against microorganisms. Citral is unstable and hydrophobic under normal storage conditions, so it can easily lose its bactericide activity. Nanoemulsion technology is an excellent way to hydrophilize, microencapsulate, and protect this compound. In our studies, we used a mixed surfactant to form citral-in-water nanoemulsions, and attempted to optimize the formula for preparing nanoemulsions. Citral-in-water nanoemulsions formed at So 0.4 to 0.6 and ultrasonic power of 18 W for 120 seconds resulted in a droplet size of < 100 nm for nanoemulsions. The observed antimicrobial activities were significantly affected by the formulation of the nanoemulsions. The observed relationship between the formulation and activity can lead to the rational design of nanoemulsion-based delivery systems for essential oils, based on the desired function of antimicrobials in the food, cosmetics, and agrochemical industries.

Effects of oligosaccharides on phase transition temperatures and rheological characteristics of waxy rice starch dispersion.

BACKGROUND: The creation of starch-based foods incorporated with functional ingredients such as probiotics is of great current interest in the food industry. This study aimed to investigate the effects of prebiotic oligosaccharides on the phase transition temperatures and rheological characteristics of waxy rice starch dispersions. Four oligosaccharides were applied to the rice starch dispersions: chitooligosaccharides, fructooligosaccharides, isomaltooligosaccharides and xylooligosaccharides. RESULTS: The addition of 125 g kg(-1) oligosaccharides elevated the onset and peak temperatures for gelatinisation of 200-400 g kg(-1) waxy rice starch dispersions. The temperature of the storage modulus (G') for gelatinisation increased markedly on adding fructooligosaccharides to 200-300 g kg(-1) waxy rice starch. For gelatinisation of 300 g kg(-1) rice starch dispersion the effectiveness of the oligosaccharides in changing the above parameters was as follows: chitooligosaccharides > fructooligosaccharides > isomaltooligosaccharides > xylooligosaccharides. Moreover, their effectiveness was dependent on the amylose content, as illustrated by comparing waxy and non-waxy rice starches (amylose contents 9-256 g kg(-1)). Importantly, the logarithmic G'(95) change was linearly and negatively correlated with amylose content. CONCLUSION: The results suggest that oligosaccharide-containing rice starch dispersions may potentially be used for the formulation of oligosaccharide-containing starchy functional foods owing to the rheological changes of these starch dispersions.

Effects of micronization on the physico-chemical properties of peels of three root and tuber crops.

BACKGROUND: The aim of this study was to investigate the effect of micronization on the physicochemical properties of the peels of root and tuber crops, including yam (Dioscorea alata L.), taro (Colocasia esculenta L.) and sweet potato (Ipomea batatas L.). Two continuous milling sections, including hammer milling and ball milling, were applied to three samples to obtain micro-sized particles of root and tuber peels. The micronization by ball-milling treatment for 10 h was carried out to investigate the distribution of particle sizes and the changes in physiochemical properties. RESULTS: The results indicate that the peels of three crops appeared to be significantly decreased in particle size after 10 h of ball-milling treatment. Moreover, the ball-milling treatments resulted in the redistribution of fiber components from insoluble fiber to soluble fiber. The micronization treatments decreased the bulk density but increased the solubility and water-holding capacities of the micronized peels. CONCLUSION: Our findings suggested that micronization treatments can improve functional properties of the fiber components of micronized peels, which provide a good source of dietary fiber in food applications.

Effect of Monascus-fermented products on learning and memory in the SAMP8 mice.

The purpose of this study was to evaluate the impact of Monascus-fermented products (MP) as regards certain changes in behavior for SAMP8 mice. Both male and female SAMP8 mice were fed a 0.03% MP diet from 3 mo of age to 11 mo of age. The results indicated that the grading score of passive avoidance behavior was significantly lower in the MP diet groups than in the control diet groups in both male and female SAMP8 mice (p < 0.05). The MP diet-augmented test-animal body weight, feed intake and feed efficiency did not differ significantly from the corresponding values for control mice. The MP diet-fed mouse group revealed significantly improved learning and memory as revealed by average escape-response testing score when comparing with control mice (p < 0.05). Further, the level of serum triglyceride and total cholesterol for the MP-fed group were shown to be significantly lower than for the control group of SAMP8 mice at 11 mo of age. The test mice fed an MP diet appeared to be significantly lower in aging score than the control group (p < 0.05). The MP diet-fed mouse group revealed significantly improved total antioxidation of liver. Subsequent to supplementation of SAMP8 mice diets with MP for a period of 8 mo, these MP-fed mice revealed significantly lower lipofuscin-cell numbers within the hippocampus (p < 0.05). The results suggest that dietary supplementation with MP might improve both learning and memory behaviour, and retard the aging process for SAMP8 mice.