Effect of Preliminary Treatment by Pulsed Electric Fields and Blanching on the Quality of Fried Sweet Potato Chips

Pulsed Electric Field Treatment of Sweet Potatoes to Reduce Oil and Acrylamide in Kettle Chips

The purpose of this investigation was to utilize pulsed electric field (PEF) technology to make sweet potato kettle chips (SPKC) healthier by lowering the amount of oil absorbed and reducing the amount of acrylamide formed during frying. Sweet potatoes were treated continuously in an Elea PEF Advantage Belt One system and prepared as SPKC, without peeling and sliced to a thickness of 1.7 mm. The specific energy for PEF application was set to either low (1.5 kJ/kg) or high (3.0 kJ/kg) with a field strength of 1.0 kV/cm and a pulse width of 6 μm. Batches of 500 g unrinsed potato slices were fried in canola oil at 130 °C for 360 s. The oil content in 3.0 g of fried SPKC was 1.39 g or 46.3%, whereas the oil content was 37.9% for high and 37.7% for low PEF-treatment conditions. Acrylamide (AA) in the fried SPKC was quantified by mass spectrometry to be 0.668 μg/g in the non-PEF control and 0.498 μg/g for low and 0.370 μg/g for high PEF treatment. The results of this study support the use of PEF in SPKC processing to reduce oil absorbance during frying by up to 9% and lower AA by up to 45%.

Effect of different pre-treatment on acrylamide content, nutrition value, starch digestibility and anthocyanin bioaccessibility of purple sweet potato (Ipomoea batata) deep-fried chips

Veggie chips have gained popularity in the European market. These are considered healthier than potato chips by consumers. However, few works evaluate their nutritional and digestibility. The current work aimed to evaluate the effect of four pre-frying treatments (soaking, blanching, pulsed electric field (PEF) and PEF + blanching combination (PEFB)) on the chemical composition, anthocyanins, acrylamide, and digestive behavior (starch hydrolysis and anthocyanins bioaccessibility) of purple sweet potato deep-fried chips. In total 15 independent batches were made, three for each studied treatment (also a control without pretreatment was developed). The studied pretreatments impacted on fat and starch content, especially blanching and PEFB, which caused an increase in fat absorption and break starch, generating maltodextrins. Nineteen anthocyanins were detected, mainly cyanidin and peonidin derivatives, but a drastic loss was observed in blanched, PEF-treated and PEF-B-Treated chips. Acrylamide values ranged from 504.11 to 6350.0- μg/kg, with the highest values reported by untreated chips and the lowest by PEF-B-treated chips (p < 0.05). The anthocyanin's bioaccessibility ranged between 66.57 and 92.88%, with soaked chips that showed the highest values.

Validation of a Passive Solar Drying System Using Pineapple

Wasted produce is a pertinent issue in agriculture, with billions of tons of produce going to waste even before it hits markets. Specifically, in Sub-Saharan Africa (SSA), nearly half of all produce is lost before market. To combat this, the Agricycle® passive solar drier was designed to provide a cost-effective method of drying fruit for preservation. Using a psychrometric chamber to simulate the SSA environment, vitamin C, total phenolic contents, and iron tests were conducted, along with microbial content determination, water content determination, dissolved solids testing, and color and microstructure analyses to validate passive solar drying, comparing the results to freeze-dried samples. Nutritional contents were comparable between fresh, freeze-dried, and solar-dried samples, with a loss in vitamin C (statistically significant), total phenolic contents, and dissolved solids during solar drying. The microbial analysis for solar-dried samples was below standard limits, and the water content in the solar-dried samples was ~10% w.b. (<20% w.b.) compared to ~3% w.b. of the freeze-dried samples. Although having comparable vitamin C, total phenolic contents, and iron values, freeze-dried and solar dried samples showed very different colors and microstructures based on colorimetry and SEM imaging. In conclusion, the Agricycle® passive solar drier is a promising alternative approach for food preservation.

The Influence of the Vacuum Impregnation, Beetroot Juice, and Various Drying Methods on Selected Properties of Courgette and Broccoli Snacks

The drying process is used in the food industry to extend the shelf life of fruits and vegetables without the use of preservatives. As quality, visual, and aroma characteristics are important determinants of consumer interest, they play a key role in the development of new foods. In the present study, vacuum impregnation (VI) was used prior to vacuum drying (VD) and freeze drying (FD) of courgette and broccoli. Organic beet juice was used to produce the novel snacks. The study showed that the use of vacuum impregnation significantly affected the VOCs profile (volatile organic compounds profile), in which the following compounds were found: viz: 2-(E)-hexen-1-ol, 2-(Z)-hexen-1-ol and aceto-phenone. VI caused a decrease in volumetric gel index (VGI), drying shrinkage (S), water activity (AW), decreased color saturation (∆C), and increased dry matter content (DM). All these properties testify to the positive effect of the pretreatment used. The drying methods used had a significant effect on the properties of the dried vegetables. The dries obtained by the FD method showed higher density and water activity, as well as better preserved color (lower ∆E) and higher VOCs, so it is considered that freeze drying is a suitable method for obtaining novel courgette and broccoli snacks.