Freeze drying of ash gourd juice with carrier agents and evaluation of physicochemical and techno-functional properties

This study was undertaken to develop ash gourd juice powder (AGP) with the assistance of different carrier agents viz., Maltodextrin (MD), Gum Arabic (GA), Soy Protein Isolate (SPI) in different proportions by freeze-drying. The carrier agents were added in 1:10, 3:20 and 1:5 (w/v) to study their effect on the physicochemical properties like moisture content, color and techno-functional properties like powder recovery, bulk density, tapped density, Hausner ratio, Carr index, swelling capacity, water and oil holding capacity, water solubility index and hygroscopicity. GA as carrier agent had reported the highest yield (16.04%) followed by samples with SPI and MD as carrier agents. AGP produced with maltodextrin (1:5) showed more lightness (L*) than MD (1:10) and MD (3:20) whereas, GA based sample at 1:5 showed more lightness (L*) than SPI (1:5). AGP samples with SPI as carrier agent showed higher moisture content (MC), bulk density (BD) and tapped density (TD) compared to GA and MD added samples. Also, the moisture content, bulk density and tapped density of dried powders decreased with an increase in carrier agents proportion. Dried AGP obtained from MD as carrier agent showed more oil holding capacity and the sample with a carrier agent showed better water holding capacity. Higher swelling capacity was observed in samples with MD (1:5) as a carrier agent than (1:10) and (3:20). Powder with MD as a carrier agent showed higher water solubility index (WSI%) with a trend of increase in carrier agent proportion. However, hygroscopicity (HY%) was higher in samples with MD compared to samples with SPI and GA. Also, the HY% decreased with an increase in carrier agent proportions. The wettability of AGP decreased with an increase in carrier agent proportion. Powder obtained through GA as a carrier agent took more time than other carrier agents like SPI and MD. Overall, the study indicated that ash gourd can be dried by using freeze dryer to protect techno-functional and physicochemical properties. Further, the nutritive composition of the samples needs to be assessed to evaluate the change in composition after freeze drying