Impact of novel far‐infrared frying technique on quality aspects of chicken nuggets and frying medium

Tailoring the physicochemical properties of starch: impact of integrated ultrasonic and ethanol pretreatment on the oil uptake of infrared fried ginkgo seeds

BACKGROUND

The structural changes of starch would have a more crucial impact on oil absorption and quality changes in starch-rich fruits and vegetables during frying process with enhanced heat transfer (such as infrared frying). In the present study, the influence of integrated ultrasonic and ethanol (US + ethanol) pretreatment on oil uptake in infrared fried (IF) ginkgo seeds was evaluated regarding modifications in the physicochemical properties of starch. The pretreatment was performed with ultrasonic (40 kHz, 300 W) and ethanol osmotic (95%, v/v) treatment individually or integrated for 40 min.

RESULTS

The mass transfer in the pretreatment was facilitated by combined ultrasound and ethanol. The swelling power, solubility, and gelatinization degree of starch was significantly increased. Low-frequency-NMR curves and images revealed that the bound water fraction in ginkgo seeds was increased and the water distribution was homogenized. The results of Fourier transform-infrared spectrum and differential scanning calorimeter revealed that the crystalline regions of starch were reduced and the thermal enthalpy was decreased after US + ethanol pretreatment. The total, surface and structural oil content in IF ginkgo seeds with US + ethanol pretreatment was reduced by 29.10%, 34.52% and 29.73%, respectively. The US + ethanol pretreatment led to a thinner crust layer with increased porosity and smaller-sized pores in the IF ginkgo seeds as observed by stereo microscopy and scanning electron microscopy.

CONCLUSION

The changes in structural and physicochemical properties of starch by combined ultrasound and ethanol affect the crust ratio and pore characteristics in fried high-starch fruits and vegetables, thereby reducing oil absorption. © 2024 Society of Chemical Industry.

Influence of cooking techniques on food quality, digestibility, and health risks regarding lipid oxidation

Foods undergo various physical and chemical reactions during cooking. Boiling, steaming, baking, smoking and frying are common traditional cooking techniques. At present, new cooking technologies including ultrasonic-assisted cooking, vacuum low-temperature cooking, vacuum frying, microwave heating, infrared heating, ohmic heating and air frying are widely studied and used. In cooking, lipid oxidation is the main reason for the change in lipid quality. Oxidative decomposition, triglyceride monomer oxidation, hydrolysis, isomerization, cyclization reaction and polymerization occurred in lipid oxidation affect lipids' quality, flavor, digestibility and safety. Meanwhile, lipid oxidation in cooking might cause the decline of lipid digestibility and increase of health risks. Compared with the traditional cooking technology, the new cooking technology that is milder, more uniform and faster can reduce the loss of lipid nutrition and produce a better flavor. In the future, the combination of various cooking technologies is an effective strategy for families to obtain healthier food.

Lignocellulosic Biomasses from Agricultural Wastes Improved the Quality and Physicochemical Properties of Frying Oils

In this work, the effects of using natural lignocellulosic-based adsorbents from sugarcane bagasse (SC), cornstalk piths (CP), and corn cob (CC) on the physicochemical properties and quality of fried oils were studied. The properties of lignocellulosic biomasses were examined using X-ray diffraction (XRD), scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FTIR). Moreover, the changes in the physicochemical properties of fresh, fried oils (for 4, 8, 12, 16 and 20 h) and adsorbents-treated oils were examined. The XRD results revealed that SC and CP biomasses have more amorphous regions than CC biomass, which had the highest crystallinity percentage. The results also showed that lignocellulosic biomasses enhanced the quality of the used oils. SC was the most effective biomass to enhance the properties of the used sunflower oil. For instance, the acid value of oil samples fried for 20 h reduced from 0.63 ± 0.02 to 0.51 ± 0.02 mg KOH/g oil after SC biomass treatment. For the peroxide value, the SC biomass treatment reduced it from 9.45 ± 0.56 (fried oil for 20 h) to 6.91 ± 0.12 meq O₂/kg. Similarly, SC biomass adsorbent reduced the p-Anisidine Value (p-AV) of the used oil (20 h) from 98.45 ± 6.31 to 77.92 ± 3.65. Moreover, SC adsorbents slightly improved the lightness of the used oils (20 h). In conclusion, natural lignocellulosic biomasses, particularly SC, could be utilized as natural adsorbents to improve the oil quality. The results obtained from this study could help in developing sustainable methods to regenerate used oils using natural and cheap adsorbents.

Recent advances in physical fields-based frying techniques for enhanced efficiency and quality attributes

Frying is one of the most common units in food processing and catering worldwide, which involves simultaneous physicochemical and structural changes. However, the problems of traditional frying technology, such as low thermal utilization and poor processing efficiency, have been gradually exposed to industrial production. In this paper, strategies of applying physical fields, such as pressure field, electromagnetic field, and acoustic field in frying technology separately or synergistically with improved efficiency and quality attributes are reviewed. The role of physical fields in the frying process was discussed with modifications in heat and mass transfer and porous structures. The effects of physical fields and their processing parameters on moisture loss kinetics, oil uptake, texture, color, and nutrients retention of fried food are introduced, respectively. Recent advances in multi-physical field-based frying techniques were recommended with synergistic benefits. Furthermore, the trends and challenges that could further develop the multi-physical field-based frying techniques are proposed, showing further commercial prospects for the purpose. The application of physical fields has brought new inspiration to the exploitation of efficient and high-qualified frying technologies, while higher technical levels and economic costs need to be taken into consideration. HighlightsThe role of physical fields in pretreatments and frying process were reviewed.The mechanism of physics fields on frying efficiency and quality was summarized.The physicochemical and microstructure changes by physics fields were discussed.The synergy of physical fields in frying technology were outlined.The trends for further multi-physical field-based frying techniques were proposed.

Can the Image Processing Technique Be Potentially Used to Evaluate Quality of Frying Oil?

The objective of this study was to investigate the feasibility of a computer vision system (CVS) for assessing the contact angle of frying oil. The oil was used to fry carbohydrate- and protein-based foods for 40 h, and the oil was collected for measuring free fatty acids (FFA), peroxide value (PV), total polar materials (TPMs), and FOS reading (dielectric constant). The results showed that FFA linearly increased with frying time (R2 > 0.95) while the polynomial correlation between TPMs and FOS reading as a result of time was observed (R2 > 0.97). The contact angle obtained from CVS was highly correlated with all chemical qualities (R2 > 0.94), except PV. In addition, the contact angle models could be used to adequately predict FFA, TPMs, and FOS reading of frying oil (R2 > 0.91). This result suggested that the image processing technique through CVS could be an appropriate alternative to chemical analysis, especially for small- and medium-scale industrial frying.