Water loss and partitioning of the oil fraction of mushroom chips using ultrasound-assisted vacuum frying

Recent studies on alternative technologies for deep-fat frying

Deep fat fried food products have been considered as a vital dietary contributor to certain chronic diseases, including the risk of atherosclerosis, cancer and hypertension. Hence, many food industries are focusing on low fat fried products to attract consumers. In general, oil is absorbed during deep fat frying, and this century old process is used for preparing various kinds of fried food products such as potato chips, banana chips, savory snacks, etc. Vacuum frying, electric field frying and two-stage frying technologies have been developed as an alternatives to traditional frying. These two technologies are suitable for most fried products; however, they may not be suitable for sugar based fruits as they can lead to the formation of browning reactions, which are generally considered unacceptable. This review aims to cover recent work done in the area of vacuum frying and two-stage frying, including the role of pre-treatment and post-treatment novel methods. Additionally, emphasis has been given on recent innovations to improve the quality of vacuum and two-stage frying, particularly concerning the reduction of oil uptake in fried food products.

A comprehensive review of the application of ultrasonication in the production and processing of edible mushrooms: Drying, extraction of bioactive compounds, and post-harvest preservation

Edible mushrooms are high in nutrients, low in calories, and contain bioactive substances; thus, they are a valuable food source. However, the high moisture content of edible mushrooms not only restricts their storage and transportation after harvesting, but also leads to a shorter processable cycle, production and processing limitations, and a high risk of deterioration. In recent years, ultrasonic technology has been widely applied to various food production operations, including product cleaning, post-harvest preservation, freezing and thawing, emulsifying, and drying. This paper reviews applications of ultrasonic technology in the production and processing of edible mushrooms in recent years. The effects of ultrasonic technology on the drying, extraction of bioactive substances, post-harvest preservation, shelf life/preservation, freezing and thawing, and frying of edible mushrooms are discussed. In summary, the application of ultrasonic technology in the edible mushroom industry has a positive effect and promotes the development of this industry.

Research progress and application of ultrasonic- and microwave-assisted food processing technology

Microwaves are electromagnetic waves of specific frequencies (300 MHz-3000 GHz), whereas ultrasonic is mechanical waves of specific frequencies. Microwave and ultrasonic technology as a new processing method has been widely used in food processing fields. Combined ultrasonic and microwave technology is exploited by researchers as an improvement technique and has been successfully applied in food processing such as thawing, drying, frying, extraction, and sterilization. This paper overviews the principle and characteristics of ultrasonic- and microwave-assisted food processing techniques, particularly their combinations, design of equipment, and their applications in the processing of agricultural products such as thawing, drying, frying, extraction, and sterilization. The combination of ultrasonic and microwave is applied in food processing, where microwave enhances the heating rate, and ultrasonic improves the efficiency of heat and mass transfer. The synergy of the heating effect of microwave and the cavitation effect of ultrasonic improves processing efficiency and damages the cell structure of the material. The degradation of nutrient composition and energy consumption due to the short processing time of combined ultrasonic and microwave technology is decreased. Ultrasonic technology, as an auxiliary means of efficient microwave heating, is pollution-free, highly efficient, and has a wide range of applications in food processing.

New preservation and detection technologies for edible mushrooms: A review

Edible mushrooms are nutritious, tasty, and have medicinal value, which makes them very popular. Fresh mushrooms have a high water content and a crisp texture. They demonstrate strong metabolic activity after harvesting. However, they are prone to textural changes, microbial infestation, and nutritional and flavor loss, and they therefore require appropriate post-harvest processing and preservation. Important factors affecting safety and quality during their processing and storage include their quality, source, microbial contamination, physical damage, and chemical residues. Thus, these aspects should be tested carefully to ensure safety. In recent years, many new techniques have been used to preserve mushrooms, including electrofluidic drying and cold plasma treatment, as well as new packaging and coating technologies. In terms of detection, many new detection techniques, such as nuclear magnetic resonance (NMR), imaging technology, and spectroscopy can be used as rapid and effective means of detection. This paper reviews the new technological methods for processing and detecting the quality of mainstream edible mushrooms. It mainly introduces their working principles and application, and highlights the future direction of preservation, processing, and quality detection technologies for edible mushrooms. Adopting appropriate post-harvest processing and preservation techniques can maintain the organoleptic properties, nutrition, and flavor of mushrooms effectively. The use of rapid, accurate, and non-destructive testing methods can provide a strong assurance of food safety. At present, these new processing, preservation and testing methods have achieved good results but at the same time there are certain shortcomings. So it is recommended that they also be continuously researched and improved, for example through the use of new technologies and combinations of different technologies. © 2023 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.

Optimization of the frying process in relation to quality characteristics of Khaja (A traditional sweet)

The present study was focused on the optimization of process parameters and quality characterization of Khaja. A full factorial design 53 was applied using different levels of fat proportions (5-25%), frying temperature (160-200 °C), and frying time (1-5 min). The response optimizer function in Minitab 18 software was used to select five samples with the highest desirability which were then subjected to sensory analysis. The lightness of the samples decreased significantly (P ˂ 0.05) from 68.59 to 43.33 whereas, redness increased significantly (P ˂ 0.05) from 0.26 to 11.48 with increasing levels of all independent variables. Water activity and moisture content of the samples decreased significantly (P ˂ 0.05) from 0.75 to 0.21 and 14.41-1.40%wb respectively, whereas total fat content increased significantly (P ˂ 0.05) from 25.05 to 45.7% with increasing levels of independent variables. The hardness of the samples significantly (P ˂ 0.05) varied from 60.45 to 7.69 N. The sensory analysis revealed that the sample with 20% fat proportion, fried at 180 °C for 4 min, scored maximum in overall acceptability. The microstructural images revealed the structural damage and formation of pores in fried samples. The fatty acid analysis showed higher saturated fatty acids in market samples than in optimized samples. The results of the study concluded that fat proportion and frying parameters (temperature and time) are crucial for a better understanding of the deep-frying process of Khaja in order to achieve good quality.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-022-05509-x.

Monitoring the Changes in Heat Transfer and Water Evaporation of French Fries during Frying to Analyze Its Oil Uptake and Quality

The effect of frying temperature on heat transfer, water loss kinetic, oil uptake kinetic, and quality of French fries was evaluated. With increasing frying temperature, the core temperature of fries increased, and the Biot number and heat transfer coefficient (h) first decreased and then increased significantly (p < 0.05). The water loss rate (kw) and water effective diffusion of fries increased with the increasing frying temperature. The kw of fries fried at 150−190 °C were 0.2391, 0.2414, 0.3205, 0.3998, and 0.3931, respectively. The oil uptake rate (ko) first increased and then decreased with increasing frying temperature, and the ko of samples fried at 150−190 °C were 0.2691, 0.2564, 0.4764, 0.3387, and 0.2522, respectively. There were significant differences in the a*, L*, ΔE, and BI between fries with different temperatures (p < 0.05), while there was no significant difference in the b* (p > 0.05). The hardness and crispness of fries increased with increased frying temperature. The highest overall acceptability scores of fries were fried at 170 °C. Therefore, the changes in color, texture overall acceptability, and oil content were due to the Maillard reaction and the formation of porous structure, which was induced by h and water evaporation of fries when they changed.

Comparison of non-volatile flavor compounds in Stropharia rugosoannulata soup processed by different methods

In this study, we investigated the non-volatile flavor compounds (5'-nucleotides, free amino acids, organic acids and soluble sugars) in Stropharia rugosoannulata soup under different processing treatments. S. rugosoannulata soups were first obtained from S. rugosoannulata powder of three different particle sizes under both thermal and non-thermal treatments. Then, the effects of processing methods on non-volatile compounds in these S. rugosoannulata soups were investigated. Specifically, the non-thermal treatment of high hydrostatic pressure (HHP) resulted in high levels of equivalent umami concentration (EUC, 827.44-1411.79 mg/100 g DM); ultrasonic treatment (UT) and homogenization (HG) led to high concentrations of soluble sugars (15.58-30.48 mg/g DM); while hot treatment (HT) contributed to high contents of total organic acids (65.52-98.39 mg/g DM). Besides, moderate fine grinding of S. rugosoannulata powder (P2) facilitated the release FAAs (free amino acids) and soluble sugars in the soup. These results suggested that HHP-P2 is beneficial to the preservation of non-volatile compounds in S. rugosoannulata soup. Our findings may improve the utilization of S. rugosoannulata in the soup industry.

Optimization of Osmotic Dehydration of White Mushrooms by Response Surface Methodology for Shelf-Life Extension and Quality Improvement of Frozen End-Products

Button mushrooms (Agaricus bisporus), one of the most common edible mushroom species, are sensitive to damages because of the absence of a protective skin layer and have a limited shelf life. Osmotic dehydration (OD), mainly used as a pre-processing step of conventional preservation methods, has been proposed as an efficient, mild treatment to preserve mushroom superior quality. In this study, response surface methodology, coupled with a Box–Behnken design, was used to investigate the effect of glycerol concentration (30–50%), temperature (30–50 °C), and duration of osmosis (0–180 min) in order to optimize the process prior to a subsequent freezing step. For each response, including mass transfer and selected quality indices, a second-order polynomial model was developed, and all process factors were found to have a significant impact. Based on the desirability approach and pre-set criteria, optimum operating conditions were estimated, namely osmosis at 50 °C, for 120 min, with a 42% glycerol solution, and the corresponding validation experiments were performed. Based on the error estimated between experimental and predicted values, polynomial equations were found to adequately predict parameter values. Based on a shelf-life test under frozen storage, OD-treated samples retained better quality attributes compared to their untreated counterparts.