Raphanus sativus (L.) var. caudatus Alef (Thai rat-tailed radish), Brassica juncea (L.) Czern. (leaf mustard) and Brassica juncea (L.) Coss. var. sareptana Sinskaja (mustard green) are cruciferous vegetable commonly consumed in Thailand and Asian countries. The vegetables were extracted with different solvents namely methanol, hexane and water prior to total phenolic content (TPC), phenethyl isothiocyanate (PEITC) content and antioxidant activity by ferric reducing antioxidant power (FRAP) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay were determined. Effects of gastrointestinal digestion on stability of these characteristics were investigated. It was found that the order of extraction efficiency for high bioactive compounds and antioxidant activity was water> methanol> hexane. Among vegetables, mustard green showed the highest TPC, PEITC, FRAP and DPPH values being 19.78±0.01 g GAE, 9.65 ± 1.08 µmol, 8.18±0.01 µM FeSO4 and 7.75±0.31 µM TE per 100g, respectively. Decreases in DPPH (30.6-53.5%), FRAP (49.0-88.0%) and PEITC (27.2-56.7%) values were slightly higher than TPC (27.9-41.6%) after in vitro digestion. It can be said that Thai cruciferous vegetables contain substantial chemical property and this may promote their health protection but the stability through digestive system should be warranted.

The influence of osmotic dehydration (OD) in combination with vacuum impregnation (VI) technique on the mass transfer behavior of “Phulae” pineapple was investigated. Pineapple slices of 10 mm thick were immersed in sucrose solution at concentrations of 55 and 65oBrix under atmospheric pressure or vacuum pressures at 250 mmHg (VOD-250) and 450 mmHg (VOD-450). The results deduced that 65o Brix of sucrose solution for 300 min and the vacuum pressure of VI at 450 mmHg were necessitated to increase solute uptake to 14.79 g/100 g when compared to other treatments. Surprisingly, the effect of OD and VI on water loss was not much different. Scanning electron microscope (SEM) showed that the pore sizes of pineapple slices were decreased when the impregnation period increased implying the higher adsorption of sucrose into the fruit structure. Subsequently, calcium lactate (Ca-L) at 2, 4 and 6% (w/w) was incorporated in sucrose solution prior to drying at 60oC in a conventional hot air dryer. It was observed that increasing concentration of Ca-L led to a significant decrease in moisture content (17.74 to 15.53%) and water activity (0.58 to 0.56) whereas calcium content was increased (24.472 to 676.317 mg/100g). However, it should be noted that high concentration of Ca-L had adverse effect on sensory property where overall actability decreased from 7.09 to 5.65 as well as total phenolic content (TPC) (17.74 to 15.53 gGAE/100g), DPPH (223.51 to 159.7 µmol Trolox/100g) and FRAP (380.65 to 291.57 µmol ascorbic acid/100g) values.

Improving benefits and reducing risk of staple food consumption are of interest among researchers nowadays. Rice is the major staple foods consumed in Asia. It has been reported that rice consumption has a positive association with the risk of chronic diseases. The effects of rice variety and preparation process on chemical characteristics of rice were investigated in the current study. Three Thai rice varieties, Khao Dok Mali 105 (KDML 105), Sao Hai (SH) and Riceberry (RB), underwent parboiling or non-parboiling as well as polishing or non-polishing prior to chemical property analysis. It was found that parboiling process possessed greater content of mineral as indicated by ash content as well as fiber and total phenolic content (TPC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity when compared to non-parboiling treatments, whereas the reduction in amylose and TAC content, GI value and starch digestibility were observed in this sample. On the other hand, polishing process led to reduction in ash, amylose, fiber, TPC and TAC content and DPPH values. GI value and starch digestibility of non-parboiled rice were lowest in SH, RB and KDML 105, respectively. However, with parboiling treatment, GI values among rice varieties were not significantly different. It can be concluded that natural composition of each rice variety is different and it affects human health. However, preparation process can alter the chemical property of rice as well as influence health benefit of rice.