Effects of ultrasound pretreatments on the quality of fried sweet potato (Ipomea batatas) chips during microwave‐assisted vacuum frying

Abstract

The research was focused on the quality of sweet potato chips fried by microwave‐assisted vacuum frying (MVF) pretreated by ultrasound. Fresh sweet potato slices were pretreated at two different ultrasonic conditions: (1) ultrasound power of 150, 300, and 450 W for 20 min and (2) ultrasound power of 300 W for 10, 20, and 30 min. The pretreated samples were then fried by MVF. The dielectric properties, drying time, moisture content, oil uptake, texture, color, and microstructure profiles of the fried sweet potato chips were measured to determine the effects of ultrasound pretreatments on the quality of the fried sweet potato slices. This study found that the dielectric properties of the fresh sweet potato slices was significantly (p < .05) changed by ultrasound pretreatments. The moisture content and oil uptake of the fried sweet potato chips was reduced constantly by increasing the ultrasound pretreatments power and prolonging the processing time. The stronger ultrasound power and the longer processing time resulted into a crispier texture property of the fried sweet potato chips. However, the strong ultrasound power level and the prolonged processing time also caused the negative effect on the color preservation and cell integrity of fried samples. In conclusion, a proper ultrasound power level and time have to be selected to produce fried sweet potato chips with less oil uptake, crisper texture, and better appearance. Practical applications Ultrasound pretreatments have great potential to improve the quality of fried food products. Ultrasound pretreatment before frying is a novel method for fabricating food products with healthier attributes, better appearance, more natural color and less frying time. The research found that, ultrasound pretreatments with proper ultrasound power level and processing time can produce higher quality products and shorten frying time.

Nonthermal pretreatments enhances drying kinetics and quality properties of dried ginger (Zingiber officinale Roscoe) slices

“…To overcome the above limitations, several nonthermal pretreatment techniques such as high hydrostatic pressure, chemical pretreatment, osmotic dehydration (OD), pulsed electric field, ultrasound (US), inert gas treatments, and cold plasma have been utilized to enhance the drying processing (Bevilacqua et al, ; Corrêa, Rasia, Mulet, & Cárcel, ; Kaur & Sogi, ; Qiu, Zhang, Wang, & Bhandari, ; Wang, Xu, Wei, & Zeng, ). These techniques offer several advantages for food pretreatment such as improving energy efficiency, reducing processing time, enhancing drying rates, and product quality (Ortega‐Rivas & Salmerón‐Ochoa, ).…”

A promising natural purple batter system with antioxidant activity for vacuum fried breaded shrimp

“…The different batter systems would influence the color of the breaded shrimps. The color changes of the vacuum fried breaded shrimps were measured by analyzing the color parameters, namely, L*, a*, b* and ΔE (Qiu et al, 2018). The effects of the different batter systems on the color of the breaded shrimps are presented in Table 3.…”

Calcium chloride impregnation of potato slices using ultrasound to reduce oil absorption during frying

“…Results from CCD analysis (Table 5) It is possible that the cell wall raptures when the product is sonicated for prolonged time (Pieczywek et al, 2017;Qiu et al, 2018;Shi et al, 2020) thus affecting oil absorption during frying (Mohammadalinejhad & Dehghannya, 2018) causing changes in the pore capillary pressure thus increasing the oil content of the final product. Note: X 1 = soaking time (5, 10, 30 min), X 2 = CaCl 2 concentration (1, 5, 10, 20, 50 × 10 3 ppm), X 3 = pretreatment (S, NS).…”

“…To prove our hypothesis, Ca +2 ions were delivered into potato tissues by soaking potato slices in CaCl 2 solutions with or without ultrasound; the slices were fried and oil content measured. Ultrasound has been used as a pretreatment in frying processes to assist in dehydration of products prior to frying (Karizaki, Sahin, Sumnu, & Mosavian, 2013;Mohammadalinejhad & Dehghannya, 2018;Oladejo et al, 2017;Dehghannya, Naghavi, & Ghanbarzadeh, 2016;Qiu, Zhang, Wang, &Bhandari, 2018, andAbedpour, 2018), but no studies have described the effect of ultrasound in delivering Ca +2 to plant tissue to reduce cell wall degradation. A number of mechanisms by which ultrasound can affect mass transfer are possible (Haydock & Yeomans, 2003;Knorr, Zenker, Heinz, & Lee, 2004), including cavitation (sponge effect) and microjet induced on the food material.…”

“…Ultrasound treatment if not optimized can create intercellular spaces, new pores, increase pectin solubilization, and decreased stiffness of plant tissues (Pieczywek, Kozioł, Konopacka, Cybulska, & Zdunek, 2017) what can affect increase oil absorption into potato chips. Strong ultrasound power level and prolonged processing time have shown to cause negative effect on the color and cell integrity of fried samples (Qiu et al, 2018). It is very important that this processing alternative delivers Ca +2 to the tissue adequately, without further degradation of the cellular material that could affect the oil absorption mechanism negatively.…”