Use of partial drying and freezing pre-treatments for development of vacuum fried papaya (Carica papaya L.) chips

The study reveals effect of pre-treatments, i.e., partial drying (PD), partial drying + freezing (PDF) and freezing (F) on physico-chemical, structural and sensory quality of vacuum fried papaya chips (100 °C for 28 min at 13.33 kPa). Pre-treatments significantly (p < 0.05) influenced the quality parameters of vacuum fried papaya chips. Partial drying pre-treated sample showed significantly (p < 0.05) higher reduction in oil uptake, i.e., 19.61% (d.b.) besides retaining significantly (p < 0.05) higher total phenolics content (394.07 mg/100 g gallic acid equivalent) as compared to other samples. Ascorbic acid content was retained significantly (p < 0.05) high in untreated control samples (209.81 mg/100 g). Freezing pre-treatment was found better in retaining total flavonoids, total carotenoids and antioxidant activity. The SEM micrographs of papaya chips showed dense and shriveled structure due to partial drying pre-treatment, however, more porous structure was observed in freezing pre-treated sample as compared to control. Freezing pre-treated samples were also rated high on hedonic scale for their sensory parameters, i.e., colour, crispness, taste, mouth feel, appearance and overall acceptability, which were in agreement with instrumental CIE colour values, firmness and microstructural characteristics of samples. The percent moisture, fat, protein, total carbohydrate, and ash content of freezing pre-treated vacuum fried papaya chips was found to be 1.51 ± 0.13%, 23.68 ± 0.12%, 3.42 ± 0.14%, 67.64 ± 1.78% and 3.75 ± 0.08%, respectively.