Optimization and Quality Attributes of Osmotic Solar Drying of Golden Berry ( Physalis peruviana )

Cape golden berry ( Physalis peruviana L ) has been grown in Egypt, South Africa, India, Australia and Great Britain. It has been shown golden berry provide significant health benefits because of their high antioxidants, vitamins, minerals and fiber. The plant is fairly adaptable to wide variety of soils and good crops are obtained on poor sandy ground. Fresh golden berry (Physalis peruviana L) fruits (whole and halves) were quickly immersed for 1 min at 80 ± 2 °C in different three solutions (distilled water, 0.5% NaOH and 0.5% citric acid). The immersed samples were quickly cooled with tap water to room temperature (25 ± 2 °C). Also, both whole and halves fruits were freezed at 612 ± 2 °C for 24 h, then all the previously treated samples (freezed and boiled) were osmotic dehydration immersed in 70% (w/v) sucrose solution at room temperature for 16hr, drained for 30 min. and spreaded on the drying trays for solar drying. The chemical composition, antioxidant activity, polyphynolics, flavonoids and Sensory attributes of fresh and dried fruits were evaluated. The fresh golden berry contained 0.29%, 0.18%, 18.47%, 4.56% and 1.05% of protein, fat, total carbohydrates, ash and crude fiber, respectively. It also contained a considerable amount of polyphones (7.35mg/100 g as tannic acid) and flavonoids (4.81mg/100gm. Fresh fruits produce a 45% decrease vs. the absorbance of DPPH radicals' control solution. Dried halves golden berry previously freezed as well as that previously boiled had significantly (P≤0.05) higher weight reduction than the whole fruits. Also, the pretreatment by boiling with NaOH 0.5% of whole and halve fruits had significantly (P≤0.05) higher weight reduction than the pretreated by boiling in water and citric acid 0.5%. The water loss of golden berry was closed with weight reduction of fruits. The best (P≤0.05) colour was observed in golden berry halves treated with NaOH and citric acid while the lowest colour values were detected in both whole and halves freezed golden berry. The dried halves golden berry previously boiled in H 2o had the highest (P≤0.05) ascorbic acid contents (20.59 mg/100gm) while, the previously freezed whole fruits had the lowest (11.12 mg/100gm). The moisture content of boiled halve dried golden berry were significantly lower than boiled whole. While, no significant differences (P≤0.05) were observed in dried golden berry among all pretreatments in protein, fat and total carbohydrates contents. Treating the Cape golden berry by 0.5% NaOH increased the ash content in both whole and halves fruits. Dried golden berry halves (Except the freezed halves golden berry) had significantly lower (P≤0.05) rehydration ratio compared with other dried samples. The same trend was observed with rehydration coefficient. Drying of golden berry as halves decreased (P≤0.05) the texture compared with the dried whole fruits. Generally, Boiling of halve fruits in citric acid 0.5% had the highest (P≤0.05) taste, while no significant differences (P≥0.05) was observed among the type of pretreatment solution (H2O, NaOH and citric acid) in rehydration ratio and rehydration coefficient, meanwhile the dried golden berry previously boiled in H 2O had the highest (P≤0.05) Texture (20.00 N) and ascorbic acid (18.33 mg/100gm). Also, no significant differences (P≥0.05) were observed in total polyphenolics and total flavonoids contents of dried goose berry previously boiled in citric acid and H 2O.