Abstract Moringa oleifera is an important source of nutrients and phytochemicals with beneficial bioactive properties. However, its availability must be improved through processing to transform it into storage-stable products. One of the most important processing steps is drying. The aims of this study were to investigate drying behaviour of moringa leaves under fluidized bed drying conditions and the effects of fluidized bed drying at 35, 45, 55, and 65 oC on nutritional contents of dried moringa leaves. The parameters measured were moisture contents during drying, crude protein, crude fat, crude fibre, ash, and carbohydrate. Results of chemical analysis revealed that the effects of drying on these nutrients can be significant. Moisture content of moringa leaves decreased linearly with time at the early stage of drying and became non-linear after the moisture content dropped to about 60-70% dry basis. Drying process occurred mostly in the constant rate period at low temperature and in the falling rate period at high temperature and drying behavior of moringa leaves can be best fitted using Page model. The effective moisture diffusivity during falling rate period were 4.86 x 10-13 m2/s at 35 oC, 5.70 x 10-13 m2/s at 45oC, 1.07 x 10-12 m2/s at 55oC, 1.44 x 10-12 m2/s at 65 oC.

Abstract The effect of ohmic heating on bioactive compounds in bignay (Antidesma bunius) fruit juice during ohmic heating were evaluated. The parameters measured were total phenol, anthocyanin, flavonoid, and antioxidant activity. Ohmic heating was conducted at 70, 90, and 110 °C, and samples were collected at heating times of 0, 15, 30, and 45 minutes. Electrical conductivity of bignay fruit juice increased linearly with temperature with values ranged from 0.012 S/m at 32 °C to 0.039 S/m at 110 °C. Insignificant change in total phenol was observed, while anthocyanin and flavonoid showed significant degradation and the degradation kinetics followed the first-order kinetic model. The degradation rate constants for anthocyanin ranged from 0.0016 to 0.0213 min-1 with activation energy (Ea) of 63.880 kJ/mol and the degradation rate constants for flavonoid were in the range of 0.0107 to 0.0209 min-1 with activation energy of 18.210 kJ/mol. Antioxidant activities (IC50) obtained from DPPH method ranged from 0.106-0.168 mg/mL while those obtained from ABTS method ranged from 0.131-0.161 mg/mL. The results indicate that anthocyanin and total phenol in bignay fruit juice is much more stable during heating compared to flavonoid.

Abstract Seaweed is an important global commodity since it is the source of many important products such as carrageenans, agar, alginates, and bioactive compounds. Seaweed processing is an energy intensive process since it involves heating large volumes of seaweeds in alkali solutions at high temperatures for up to six hours. To increase energy efficiency, an ohmic based processing system has been developed but has not been tested thoroughly. Therefore, the objective of this study was to identify optimum processing conditions for extraction of carrageenan from Eucheuma spinosum using ohmic heating technology. The experiment was conducted using Central Composite Design with four variables, i.e. extraction temperature, extraction duration, KOH concentration, and solution to seaweed ratio. Following the extraction process, carrageenan was recovered through precipitation using 90% isoprophyl alcohol solution. Results of experiments indicate that extraction yields varied from 29.6-62.4% dry basis with viscosity and gel strength varied from 259-290 mPa.s and 42.54-70.41 g/cm2 respectively. Statistical analysis indicated that extraction yield can be adequately modeled using the four variables and optimum extraction yield (61.59%), gel strength (53.48 g/cm2), and viscosity (284.51 mPa.s) were achieved at 95 °C extraction temperature, 240 minutes of extraction time, 0.4M KOH concentration, and 45:1 solution to seaweed ratio.

Abstract Bignay fruits are produced from wild trees of Antidesma bunius Spreng which can be found in India, Ceylon, and South East Asia countries. Each mature tree can produce hundreds of kilograms of fruits per year, so this fruit has the potential to be used as a raw material in juice and beverage industries. In addition, recent trends in consumer demand indicates that consumers are more inclined to demand products which can provide health benefits. In order to assess the potential of bignay fruit as a raw material for juice production, it is important to determine the health-promoting bioactive compounds contained in fresh bignay fruit juice. Therefore, the objective of this study was to determine the concentration of bioactive compounds in fresh bignay fruit juice. Results obtained from this study showed that bignay fruit juice contained 1202.5 mg GAE/100 mL of total phenolic, 436.602 mg/100 mL of anthocyanin, 48.931 mg/100 mL of ascorbic acid, and 3.78 mg/100 mL of flavonoid. The scavenging activities obtained from DPPH and ABTS methods were 0.110 mg/mL and 0.126 mg/mL respectively. The above results indicate that bignay fruits contain health-promoting chemical compounds and can be used as a natural source of antioxidants.