Fook Yee Chye

Banana by-products: an under-utilized renewable food biomass with great potential

Banana (Musaceae) is one of the world’s most important fruit crops that is widely cultivated in tropical countries for its valuable applications in food industry. Its enormous by-products are an excellent source of highly valuable raw materials for other industries by recycling agricultural waste. This prevents an ultimate loss of huge amount of untapped biomass and environmental issues. This review discusses extensively the breakthrough in the utilization of banana by-products such as peels, leaves, pseudostem, stalk and inflorescence in various food and non-food applications serving as thickening agent, coloring and flavor, alternative source for macro and micronutrients, nutraceuticals, livestock feed, natural fibers, and sources of natural bioactive compounds and bio-fertilizers. Future prospects and challenges are the important key factors discussed in association to the sustainability and feasibility of utilizing these by-products. It is important that all available by-products be turned into highly commercial outputs in order to sustain this renewable resource and provide additional income to small scale farming industries without compromising its quality and safety in competing with other commercial products.

Nutritional Quality and Antioxidant Activity of Selected Edible Wild Mushrooms

Five species of edible wild mushrooms were selected to determine the proximate composition, vitamins (retinol, α-tocopherol, γ-tocopherol, thiamin, riboflavin, and ascorbic acid) and mineral contents (Fe, Zn, Co, Ca, Mg, K, and Na), antioxidant activity, and total phenolics. Hygrophorus sp. showed significant higher ( p<0.05) fat content as compared to other wild mushrooms with the mean value of 6.57%. However, Polyporus tenuiculus was found to be a good source of fiber while Hygrocybe sp. was good in α-tocopherol among the mushrooms tested. The iron and calcium contents were the highest in Hyrocybe (175.64 μg/g) and Hygrophorus sp. (81.70mg/100g) respectively. The in vitro antioxidant activities of petroleum ether (PE) and methanolic extracts of the edible wild mushrooms were comparable to the cultivated oyster mushroom. The radical scavenging activity was highest for PE extract of Pleurotus sp. (85%) while methanolic extract of Hygrocybe sp. exhibited the highest (94%) chelating effect, in correlation with its significantly higher ( p<0.05) phenolics content (42.21 mg GAE/g extract). In conclusion, edible wild mushrooms can be an excellent source of micronutrients and antioxidant components.

Evaluation of probiotic potential of lactic acid bacteria isolated from traditional Malaysian fermented Bambangan (Mangifera pajang)

This study aims to evaluate the probiotic and technological properties of lactic acid bacteria (LAB) isolated from an indigenous fermentation of Bambangan (Mangifera pajang). The LAB were evaluated for their tolerance to low pH, bile salt, antimicrobial potential, auto-aggregation ability, microbial adhesion to solvents, tolerance to high temperature and osmotic pressure. Approximately 36% of the isolated LAB strains displayed excellent survival at pH 3.0 with at least 4 log CFU/ml after 24 hours at 2.0% bile salt. A high aggregation activity (>20%) was found in most of the LAB strains. Five Lactobacillus plantarum strains showed at least 70% viability at 60°C for 10 minutes while one L. brevis and three L. plantarum strains were tolerant to 6% sodium chloride. Furthermore, the maximum β-galactosidase activity was found in four L. plantarum strains. In conclusion, these LAB strains could serve as promising probiotic candidates for the preparation of functional food products.

Fermentation-Derived Bioactive Components from Seaweeds: Functional Properties and Potential Applications

ABSTRACT Seaweeds are valuable sources of biologically active compounds that could be used as ingredients for pharmacological applications. Industrial fermentation using microorganisms provides a wide array of fermented foods and functional compounds with excellent health benefits. These fermentation-derived natural compounds have the potential to be applied as nutraceuticals and functional foods. Therefore, this paper presents an overview of the fermentation of sustainable seaweeds in producing valuable components, including anticoagulant, antioxidant, antimicrobial, anti-inflammatory, and anticancer. Fermentation-derived compounds are expected to receive more attention due to their environmentally friendly processing as well as consumer desire for natural foods.

Effect of Selected Oligosaccharides on the Viability and Fermentation Kinetics of Lactobacillus acidophilus and Lactobacillus casei in Cultured Milk

The study aimed to investigate the effect of fructo-oligosaccharides (FOS) on the growth and fermentation kinetics of Lactobacillus casei LC-01 (LC) and Lactobacillus acidophilus LA5 (LA) in cultured milk. Two commercially available FOS with different degree of polymerization (DP), namely Fibrulose F97 (DP, 2-20) and Fibruline Instant (DP, 3-60) were used at 4% (w/v) and 8% (w/v) respectively during fermentation and storage of cultured milk. Physicochemical properties and acidification kinetic of milk were measured throughout the fermentation. The concentration and DP values of the FOS do not seem to affect the growth of both probiotics during fermentation. Nevertheless, the pH and total soluble solid of milk fermented by both probiotics supplemented with FOS decreased tremendously during fermentation. It is noted that the percentage of lactic acid produced in L. acidophilus is higher than L. casei owing to the metabolic characteristic of the strain. The kinetic of maximum acidification rate V max of cultured milk was significantly higher with the addition of FOSs at 4%. However, FOS with lower DP seemed to enhance (p<0.05) the stability of LA in cultured milk during cold storage, but no significant effect on LC. The results of this work indicate that FOS could significantly improve the survival of probiotics in cultured milk especially during refrigerated storage.

Influence of temperature variations on growth, injury survival and inactivation of Listeria monocytogenes in goat milk samples at laboratory scale

Transmission of the thermo-tolerant pathogen Listeria monocytogenes via contaminated milk and its products, can lead to serious food-borne illness. In this study, the effects of selected temperatures on survival, percentage injury and inactivation of L. monocytogenes in goat milk samples collected from two different farms were evaluated. Low temperature ranges (0, 5, 10 °C) had a bacteriostatic effect; while at temperatures of 25 and 45 °C, this pathogen grew luxuriantly. However, growth was comparatively slow at 15 °C throughout a 12-h stress period. Furthermore, a high temperature range (50, 55, 60 and 65 °C) resulted in the elimination of this pathogen within 4 h of stress. Results of Scanning Electron Microscopy showed morphological changes in the cells upon induction of stress temperatures.