Comparison of Vacuum and Atmospheric Deep-Fat Frying of Osmo-Dehydrated Goldenberries

Colombian goldenberries that do not reach sufficient quality for export are exposed to waste, so the search for processes that provide added value while guaranteeing the conservation of this fruit is paramount. Thus, snacks by vacuum frying from goldenberries (Physalis peruviana L.) with low export quality were made. Goldenberry slices previously subjected to ultrasound-assisted osmotic dehydration were used for this purpose. Response surface methodology with different levels of temperature (110 °C and 130 °C), vacuum pressure (0.3 bar and 0.5 bar), and time (2 min and 6 min) was used to optimize the process. At optimal vacuum frying conditions (i.e., 108 °C, 0.5 bar, and 5.5 min), snacks with lower (p ≤ 0.05) oil content were produced, compared to atmospheric frying chips. The optimized snacks had 9% oil, 7% moisture, ΔE of 13 (with respect to fresh fruit), aw of 0.3, and hardness of 14 N. The kinetics and modeling of moisture loss and oil uptake were performed under optimal conditions, obtaining the best fit with the Page (R2 = 99%) and the first-order (R2 = 96%) models, respectively. There was a clear correlation between oil uptake and moisture loss, as the highest oil retention in the product took place when the product had lost the greatest amount of water; therefore, the low initial moisture in the product due to pretreatment resulted in lower oil uptake in it. The obtained goldenberry snack showed adequate physicochemical properties, and the pretreatment yielded a product with much healthier characteristics (i.e., lower oil content, and therefore, a lower caloric intake); so, the proposed process could represent an alternative to the processing of low-export quality Colombian goldenberries.