Choon Yoong Cheok

Extraction of Total Phenolic Content from Garcinia mangostana Linn. hull. I. Effects of Solvents and UV–Vis Spectrophotometer Absorbance Method

The effect of solvents with different polarity on the extraction of total phenolic content from mangosteen hull was investigated. The Folin–Ciocalteu (FC) method, expressed in equivalent to gallic acid concentration was used to quantify total phenolic content. Methanol was the most effective solvent in giving the highest recovery (p < 0.05) of phenolic compounds, compared to ethanol, acetone, isopropanol, ethyl acetate and distilled water. Regression analysis was performed to evaluate the relationship between the direct absorbance method and the FC method for total phenolic contents determination. Strong coefficients of determinations (R2 ≥ 0.990) were obtained for the absorbance of acetone, ethanol, and methanol extracts suggesting the regression equations obtained can be used to determine the total phenolic contents without using the FC method.

Current trends of tropical fruit waste utilization

ABSTRACT Recent rapid growth of the worlds population has increased food demands. This phenomenon poses a great challenge for food manufacturers in maximizing the existing food or plant resources. Nowadays, the recovery of health benefit bioactive compounds from fruit wastes is a research trend not only to help minimize the waste burden, but also to meet the intensive demand from the public for phenolic compounds which are believed to have protective effects against chronic diseases. This review is focused on polyphenolic compounds recovery from tropical fruit wastes and its current trend of utilization. The tropical fruit wastes include in discussion are durian (Durio zibethinus), mangosteen (Garcinia mangostana L.), rambutan (Nephelium lappaceum), mango (Mangifera indica L.), jackfruit (Artocarpus heterophyllus), papaya (Carica papaya), passion fruit (Passiflora edulis), dragon fruit (Hylocereus spp), and pineapple (Ananas comosus). Highlights of bioactive compounds in different parts of a tropical fruit are targeted primarily for food industries as pragmatic references to create novel innovative health enhancement food products. This information is intended to inspire further research ideas in areas that are still under-explored and for food processing manufacturers who would like to minimize wastes as the norm of present day industry (design) objective.

Physicochemical properties and volatile profile of chili shrimp paste as affected by irradiation and heat

Chili shrimp paste (CSP) is an exotic traditional Southeast Asian condiment prepared using mainly fresh chilies and fermented shrimp paste (belacan) which attributed to strong pungent fishy odor. This study aims to evaluate the effectiveness of electron beam irradiation (EBI) exposure on CSP for microorganisms decontamination, and its physicochemical qualities changes. Changes in capsaicinoid contents and volatile compounds were analyzed using HPLC and GC-MS. Mesophilic bacteria, yeast, mold and pathogenic Enterobacteriaceae decreased as irradiation dose increasing from 0 to 10kGy. EBI at 10kGy effectively decontaminated the samples with no significant effects on phenolic and capsaicinoids contents compared to the fresh samples. From 24 compounds, irradiated CSP retained 23 volatile compounds, while thermally treated CSP has only 19 compounds. EBI at 10kGy is effective for decontamination in CSP with lesser destructive effect on volatile compounds and texture compared to thermal treatment.

The effects of satay marination on three beef muscle types.

The effects of marination on the weight gain, cooking loss and Warner-Bratzler shear force of three beef muscle types, i.e. blade roast (BR), biceps femoris (BF) and semitendinosus (ST) were investigated by treating them in distilled water (as control), brine solution, tamarind juice, tamarind juice plus salt and satay marinade for 180 minutes. The weight gain of ST muscles were significantly higher (P < 0.01) than the BR muscles in brine solution, tamarind juice plus salt and satay marinade, while ST and BF muscles did not differ significantly (P > 0.01) in all the five treatments. For cooking loss, muscle types did not show a significant difference (P > 0.01) in all marinating treatments except for BR and ST muscles in tamarind juice (P = 0.00023). The presence of salt in tamarind juice gave better results in tenderising ST muscles than using tamarind juice alone.