METHODS: The kedondong powder was dried using five methods: convection oven drying, vacuum drying, spray drying, drum drying and freeze drying. The physical properties, flowability and DPPH radical scavenging ability of dried kedondong powder were examined.
RESULTS: Spray-dried powder provided the significantly (p ≤ 0.05) highest process yield, which was 54.93%. All the powder produced had a low moisture content (3.03 to 5.66%) and water activity (0.19–0.37). Visually, whitish and fine powders were observed on spray-dried and freeze-dried samples, while convection oven-dried and vacuum-dried powder appeared yellowish and coarse. The pH of the reconstituted powders varied from 2.71 to 2.83, where drum-dried powder was the most acidic. Spray-dried powder showed the highest wettability and shortest dissolution time, which was 172.65 s and 10.55 s, respectively. With the exception of drum-dried powder, all the dried powders were classified as non-caking powders. The bulk and tapped density of the powders ranged from 0.32 to 0.70 g/mL and 0.38 to 0.86 g/mL, respectively. Vacuum-dried powder had very good flowability, convection oven-dried and drum-dried powder had good flowability, while spray-dried and drum-dried powder had fair flowability. Antioxidant assay showed that freeze-dried powder exhibited the highest free radical scavenging activity (IC50 = 701.29 μg/mL).
CONCLUSIONS: This study indicates that spray-dried kedondong powder has great potential in the food industry due to its high process yield and better powder quality. Meanwhile, freeze drying best preserved the antioxidant properties of the powder, which could potentially be used as a functional ingredient as a result. This study is important for the fruit processing industry as it offers an alternative for the farmer to produce kedondong fruit powder because the fruit has a short shelf life. Converting the fruit into powder can diversify the resulting produce into different applications, such as fruit juice, beverages, jam and other food products.
RESULTS: Studies were carried out on drying of papaya leaves using hot air (60, 70 and 80 °C), shade and freeze drying. Effective diffusivities were estimated ranging from 2.09 × 10-12 to 2.18 × 10-12 m2 s-1 from hot air drying, which are within the order of magnitudes reported for most agricultural and food products. The activation energy to initiate drying showed a relatively low value (2.11 kJ mol-1 ) as a result of the thin leave layer that eased moisture diffusion. In terms of total polyphenols content and antioxidant activities, freeze-dried sample showed a significantly higher (P
METHODS AND RESULTS: The freeze-dried L. lactis-fermented milk powder stored in 4-ply retortable polypropylene (RCPP)-polyamide (PA)-aluminium (AL)-polyethylene terephthalate (PET) and aluminium polyethylene (ALPE) was evaluated throughout 49 days of accelerated storage (38°C and 90% relative humidity). The fermented milk powder stored in 4-ply packaging remained above 6 log10 CFU g-1 viability, displayed lower moisture content (6.1%), higher flowability (43° angle of repose), water solubility (62%), and survivability of L. lactis after simulated gastric and intestinal digestion (>82%) than ALPE packaging after 42 days of accelerated storage. K-ras mimotope expression was detected intracellularly and extracellularly in the freeze-dried L. lactis-fermented milk powder upon storage.
CONCLUSIONS: This suggests that fermented milk powder is a suitable food carrier for this live oral vaccine.
RESULTS: In most cases except for oven drying, the bulk density decreased, thus increasing the porosity. This might be attributed to the increase in the inter-particle voids of smaller sized particles with larger contact surface areas per unit volume. The current study revealed that oven-dried gum and freeze-dried gum had the highest and lowest compressibility index, thus indicating the weakest and strongest flowability among all samples. In the present work, the freeze-dried gum showed the lowest angle of repose, bulk, tapped and true density. This indicates the highest porosity degree of freeze dried gum among dried seed gums. It also exhibited the highest solubility, and foaming capacity thus providing the most desirable functional properties and flow characteristics among all drying techniques.
CONCLUSION: The present study revealed that freeze drying among all drying techniques provided the most desirable functional properties and flow characteristics for durian seed gum.