Vipa Surojanametakul

Reliable enzyme-linked immunosorbent assay for the determination of coconut milk proteins in processed foods.

This study was designed to develop a novel sandwich enzyme-linked immunosorbent assay (ELISA) for the detection and quantification of coconut milk proteins in processed foods. The developed sandwich ELISA was able to detect coconut milk proteins from various coconut milk products and did not show any cross-reactivity with 41 of 42 kinds of popularly used food ingredients, thus reflecting great specificity for coconut milk proteins. In addition, the established ELISA is highly sensitive and allowed the detection of 0.31 μg/g of coconut milk protein in complex food matrices. This proposed assay could serve as a useful tool for the detection of the presence of hidden coconut milk proteins in processed foods.

Effects of Drying Methods on the Nutritional and Physical Quality of Pre-Germinated Rice

Pre-germinated rough rice (pre-GRR) and pre-germinated brown rice (pre-GBR) were dried to below 14% wet basis (w.b.) by various drying schemes involving three dryers: hot-air oven (HAO), fluidized-bed dryer (FBD), and solar dryer (SD). The aim of this research was to investigate the effects of drying methods on the γ-aminobutyric acid (GABA) content, antioxidant activity, fissuring, and color of GABA rice produced from pre-GRR and pre-GBR in order to maximize the quality of GABA rice. The HAO was operated at 50°C, while the drying temperatures for FBD were 80°C, 100°C, 120°C, and 140°C. The GABA contents of GABA rice produced from pre-GRR and pre-GBR before drying were 25.4 and 22.1 mg per 100 g dry mass of sample, respectively. The antioxidant activities of GABA rice produced from pre-GRR and pre-GBR were 32.89 and 26.11 mg BHAE (t-butylated hydroxyanisole equivalent) per 100 g sample dry mass, respectively. Both GABA content and antioxidant activity were diminished after drying, especially in the case of single-stage drying at 50°C. The multi-stage drying with intermittent tempering steps significantly reduced the fissured kernels. After drying, the lightness of samples was lowered whereas the redness and yellowness were increased. The results of this study recommend GABA rice to be produced from pre-GRR rather than pre-GBR because of its increased GABA content and antioxidant activity, lower tendency to fissuring, and similarity of color to typical brown rice.

Study of hybrid dryer prototype and its application in pregerminated rough rice drying

ABSTRACT In this study, a hybrid dyer, combining heat pump drying (HPD) with fluidized bed drying (FBD) concepts were designed and fabricated. The pregerminated rough rice (pre-GRR) was dried in multistage using this hybrid dryer to compare with the single-stage drying by hot air dryer. The objectives were to test the application of this hybrid dryer and determine the suitable drying condition for pre-GRR. The result indicated that the punched plate distributor was the most suitable distributor. The pre-GRR should be dried by the three-stage drying method using either FBD or HPD at 45°C in the last stage to obtain higher head rice yield, lower fissure grain, and better color values than their counterparts. The scanning electron micrographs proved that starch gelatinization occurred when applying FBD at temperatures between 100 and 140°C causing the adhesive connections inside the kernels and subsequent decrease in fissures.

Thai Purple Sweet Potato Flours: Characteristic and Application on Puffed Starch-Based Snacks

Characteristics and properties of 4 Thai purple sweet potato flours, Maejo 343, Phichit 65-3, Phichit 290-9 and Torperk were determined in terms of native and pre-gelatinized flours. Color, physicochemical properties and antioxidant activity of native and pre-gelatinized flours depend on their varieties. All native flours showed low redness (a*) and blueness (-b*) values but high pasting properties. Pre-gelatinized flours had a unique purple color and high antioxidant activity. Flours produced by Phichit 65-3 showed a deep intense purple color, high anthocyanins and good antioxidant activity. Both native and pre-gelatinized Phichit 65-3 flours were used as the main raw materials of air-puffed pre-gelatinized flours with different ratios at 10%, 30% and 50%. Increasing the content of pre-gelatinized flours improved color, expansion and antioxidant activity of snacks. Low hardness (9.55-11.65 kg) was presented in all snacks prepared from sweet potato flours. Purple sweet potato snacks prepared from 50% pre-gelatinized flour had good appearance, light texture, high anthocyanins and high antioxidant activity. Results showed that Thai purple sweet potato flours can be used to produce healthy snacks with improved appearance and texture. They also have potential as sources of natural colorants and antioxidants in food products.

Survey of Thai Commercial Food Products That Have Been Reported to Contain No Wheat, Rye, Barley, or Gluten According to Their Labels.

Celiac disease (CD) and gluten-related disorders are significant health and social issues in Western countries, and CD individuals need to exclude gluten from their diets. The adverse health impacts of CD have extended to Asian countries in which CD was not a problem previously. Thai commercial food products that do not contain wheat, rye, barley, or gluten on their labels were surveyed as to whether they were suitable for CD individuals by examining the absence of gluten or the presence of gluten <20 ppm. In Thailand, ELISA tested for gluten content in 129 commercial food products that contained neither wheat, rye, barley, nor gluten on their labels. One hundred nineteen of these 129 products included <20 ppm gluten, and 10 products contained >20 ppm gluten. Surprisingly, four products showed gluten levels >1%. In these 10 products, wheat presence was confirmed by PCR analysis. Our survey suggests that CD individuals can consume most of the examined Thai food products, and the survey showed the potential of these Thai products as new diets for CD patients so as to expand the limited food choices from different food cultures, and ultimately to improve the quality of life for all CD individuals globally. The appropriate gluten management strategies need to be implemented by Thai food manufacturers to ensure accurate labeling and to protect the safety of consumers with CD.