Effect of superheated-steam roasting on physicochemical properties of peanut (Arachis hypogea) oil

Analysis of physicochemical properties of nut-based milk and sweetened condensed milk alternatives

This study analyzed the physicochemical properties of nut-based milk and sweetened condensed milk (SCM) alternatives. Four types of nuts (almonds, cashews, hazelnuts, and walnuts) were roasted at 140 °C for 15 min, followed by the preparation and analysis of milk and SCM alternatives. During the production of SCM by heating with adding sugar, the pH, moisture, and L* decreased, while the carbohydrates, viscosity, and browning index increased significantly (p < 0.05). Oleic acid, linoleic acid, and linolenic acid contents were comparable among all samples (p > 0.05). Volatile compounds were analyzed using HS-SPME-GC-MS to determine changes due to roasting and heating, and a total of 54 volatile compounds were identified. These findings to show the importance of the physicochemical characteristics of milk and SCM alternatives, provide practical information for the development of improved-quality dairy alternatives.

Effect of thermal pretreatments on the quality attributes and irradiation markers of sesame oil extracted from sesame seeds without and with gamma irradiation

This study comparatively studied the effects of three thermal pretreatment methods, i.e., wet-heat (WT), roasting (RT) and microwave (MT), on the quality attributes and irradiation markers of sesame oil obtained from sesame seeds without and with gamma irradiation. Results showed that gamma irradiation had negligible effect on the quality of sesame seeds and their extracted oils. The effects of thermal pretreatments on irradiated and non-irradiated sesame seeds and their oils were similar, little synergistic effects were observed. The RT-treated oils had more carotenoids, chlorophyll, total phenols, tocopherols, and heterocyclic volatiles content, as well as longer oxidation induction time, but darker color compared with their WT- and MT-treated counterparts. All oil samples had identical FTIR spectra. Eight radiolytic hydrocarbons were identified in the irradiated sesame oils. Thermal pretreatments reduced the content of radiolytic hydrocarbons, but did not significantly change their composition. Our study helps to identify products from irradiated sesame seeds.

Peanut oils from roasting operations: An overview of production technologies, flavor compounds, formation mechanisms, and affecting factors

Fragrant peanut oils (FPOs) are commonly defined as edible peanut oils having strong natural roasted peanut flavor without peculiar unpleasant odors and produced from peanut kernels through roasting/steaming and pressing operations, etc. The flavor of FPOs plays a crucial role in their acceptability and applications and their flavor profiles are an important factor in determining their overall quality. This paper presents a systematic literature review of recent advances and knowledge on FPOs, especially their flavors, in which it is focused on the evaluation of volatile compounds, the factors influencing the formation of flavor compounds, and formation mechanisms of those typical flavor compounds. More than 300 volatiles are found in FPOs, while some key aroma-active compounds and their potential formation pathways are examined. Factors that have big influences on flavor are discussed also, including the properties of raw materials, processing technologies, and storage conditions. Ultimately, the paper highlights the challenges facing, including the challenges in flavor analysis, the relationship between volatile compounds and sensory attributes, as well as the opening of the blackboxes of flavor formations during the processing steps, etc.

Effect of radio frequency roasting on the lipid profile of peanut oil and the mechanism of lipids transformation: Revealed by untargeted lipidomics approach

Radio frequency (RF) heating has been proved an alternative roasting method for peanuts, which could effectively degrade aflatoxins and possesses the advantages of greater heating efficiency and penetration depth. This study aimed to investigate the influences of RF roasting on the lipid profile of peanut oil under 150 °C target temperature with varied peanut moisture contents (8.29 % and 20 %) and holding times (0, 7.5, and 15 min), using ultra-performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (UPLC-QTOF-MS/MS)-based lipidomics. In total, 2587 lipid species from 35 subclasses were identified. After roasting, the contents of sterol lipid (ST) and subclasses of glycerophospholipids (GPs) and glycoglycerolipids increased significantly, while fatty acid (FA), Oxidized (Ox-) FA, cholesterol (CE), and all subclasses of glycerolipids (GLs) decreased, and 1084 differential lipids were screened. The highest ST and lowest CE contents in peanut oil were achieved by medium roasting (7.5 min). The raise in moisture content of peanut simply affected a few GPs subclasses adversely. Compared with hot air (HA) roasting, RF decelerated lipid oxidation, showing higher levels of diacylglycerol, triacylglycerol and FA, with no additional negative impact and only 69 exclusive differential lipids. During RF roasting, hydrolysis and oxidation of fatty acyl chains into secondary oxides were the central behaviors of lipids transformation. This study could provide insights into the lipid changes and transformation mechanism of peanut oil by RF roasting processing.

Characteristics and Antioxidant Activity of Walnut Oil Using Various Pretreatment and Processing Technologies

This study was the first time the effects of pretreatment technology (microwave roasting, MR; oven roasting, OR; steaming roasting, SR) and processing technology (screw pressing, SP; aqueous enzymatic extraction, AEE; subcritical butane extraction, SBE) on the quality (physicochemical properties, phytochemical content, and antioxidant ability) of walnut oil were systematically compared. The results showed that the roasting pretreatment would reduce the lipid yield of walnut oil and SBE (59.53−61.19%) was the processing method with the highest yield. SR-AEE oil provided higher acid value (2.49 mg/g) and peroxide value (4.16 mmol/kg), while MR-SP oil had the highest content of polyunsaturated fatty acid (73.69%), total tocopherol (419.85 mg/kg) and total phenolic compounds (TPC, 13.12 mg/kg). The DPPH-polar and ABTS free radicals’ scavenging abilities were accorded with SBE > AEE > SP. SBE is the recommended process for improving the extraction yield and antioxidant ability of walnut oil. Hierarchical cluster analysis showed that processing technology had a greater impact on walnut oil than pretreatment technology. In addition, multiple linear regression revealed C18:0, δ-tocopherol and TPC had positive effects on the antioxidant ability of walnut oil, while C18:1n-9, C18:3n-3 and γ-tocopherol were negatively correlated with antioxidant activity. Thus, this a promising implication for walnut oil production.

Superheated steam processing: An emerging technology to improve food quality and safety

Heat processing is one of the most efficient strategies used in food industry to improve quality and prolong shelf life. However, conventional processing methods such as microwave heating, burning charcoal treatment, boiling, and frying are energy-inefficient and often lead to inferior product quality. Superheated steam (SHS) is an innovative technology that offers many potential benefits to industry and is increasingly used in food industry. Compared to conventional processing methods, SHS holds higher heat transfer coefficients, which can reduce microorganisms on surface of foodstuffs efficiently. Additionally, SHS generates a low oxygen environment, which prevents lipid oxidation and harmful compounds generation. Furthermore, SHS can facilitate development of desired product quality, such as protein denaturation with functional characteristics, proper starch gelatinization, and can also reduce nutrient loss, and improve the physicochemical properties of foodstuffs. The current work provides a comprehensive review of the impact of SHS on the nutritional, physicochemical, and safety properties of various foodstuffs including meat, fruits, and vegetables, cereals, etc. Additionally, it also provides food manufacturers and researchers with basic knowledge and practical techniques for SHS processing of foodstuffs, which may improve the current scope of SHS and transfer current food systems to a healthy and sustainable one.

The Effect of Combined Superheated Steam Roasting and Smoking on the Quality Characteristic of Alaska Pollack (Gadus chalcogrammus) Roe

Alaska pollack roe (APR) is a protein source that is usually salted and fermented, containing a high salt content. Using a combination of superheated steam roasting and smoking, we developed a new low-salt ready-to-eat APR variant, whose quality characteristics we analyzed. The optimal conditions for roasting (216 °C for 4 min) and smoking (64 °C for 14 min) were obtained from sensorial attributes using response surface methodology. Under the optimal conditions, smoke-roasted APR had an overall acceptance (OA) score of 8.89. The combination of roasting and smoking significantly increased volatile basic nitrogen (VBN, 18.6%) and decreased the total bacterial count (TBC, 38.6%), while thiobarbituric acid reactive substances (TBARS) were not affected. Smoke-roasting APR also increased its nutritional content to 30% protein with 44% essential amino acids, and more than 40% DHA and EPA in 4.3% fat. During 30 days of storage, the OA, VBN, TBARS, and TBC values significantly changed with time and storage temperature (p < 0.05). The shelf life of the product was estimated to be 24 d. In conclusion, the combination of roasting and smoking APR could improve product quality and may be an alternative to diversify processed APR.

Effect of Steam and Smoke Cooking Processes on Web-Foot Octopus (Amphioctopus sp.) Home Meal Replacement Product

In Korea, the web-foot octopus (Amphioctopus sp.) is commonly consumed as jjukkumi bokkeum, a spicy stir-fried octopus dish. Using steaming and smoking methods, we made jjukkumi bokkeum home meal replacement (HMR) products. The response surface methodology (RSM) was employed to optimize the steam and smoke processes. Quick freezing was applied to freeze the test product at −35 °C. Then, the physicochemical, biological, nutritional characteristics, and shelf-life of the test HMR products were evaluated. The optimal conditions for steaming and smoking were 95 °C for 2 min and 70 °C for 11 min, respectively. The pH, volatile basic nitrogen content, and thiobarbituric acid-reactive substances content decreased after steaming and smoking, indicating that these processes maintained these parameters well. Sensory evaluation revealed that there were no changes in these characteristics after freezing and reheating. Further, the test HMR products contained the daily nutritional requirements of macro and micronutrients, as well as amino acids and fatty acids. The shelf-life of the HMR products was estimated to be 15 months. The findings of this study indicate that the application of steam and smoke processes to produce a jjukkumi bokkeum HMR product results in a high-quality product with a long shelf-life.

Development of a Home Meal Replacement Product Containing Braised Mackerel (Scomber japonicus) with Radish (Raphanus sativus)

The coronavirus disease pandemic has contributed to increasing convenience in food preferences. Home meal replacement (HMR) products are ready-to-eat, -cook, or -heat foods, providing convenience for consumers. We developed a HMR product containing mackerel as a protein- and lipid-rich source using various food-processing technologies to maintain its nutritional content and prolong shelf life. The HMR product contained mackerel, radish, and sauce in a ratio of 5:1:4. Raw frozen mackerels were thawed by using a high-frequency defroster before being braised using a superheated steam roaster. Response surface methodology was employed to obtain the optimal heating conditions of 181 °C for 9 min. The final test HMR product was packed in a polypropylene plastic bowl prior to freezing at -35 °C for 1 h using a quick freezing system. The HMR product developed using these technologies exhibited stable microbiological and chemical properties for 90 days of storage. Sensory scores gradually decreased with increasing storage temperature and time. Protein content in the HMR product was 13%, 40% of which comprised essential amino acids; lipid content was 13.4%, 18% of which was composed of docosahexaenoic acid. The HMR product can preserve its quality and is considered safe for consumption for up to 40 months of storage at -18 °C.

An overview of conventional and emerging techniques of roasting: Effect on food bioactive signatures

Roasting is a food processingtechnique that employs the principle of heating to cook the product evenly and enhance the digestibility, palatability and sensory aspects of foods with desirable structural modifications of the food matrix. With the burgeoning demand for fortified roasted products along with the concern for food hygiene and the effects of harmful compounds, novel roasting techniques, and equipment to overcome the limitations of conventional operations are indispensable. Roasting techniques employing microwave, infrared hot-air, superheated steam, Revtech roaster, and Forced Convection Continuous Tumble (FCCT) roasting have been figuratively emerging to prominence for effectively roasting different foods without compromising the nutritional quality. The present review critically appraises various conventional and emerging roasting techniques, their advantages and limitations, and their effect on different food matrix components, functional properties, structural attributes, and sensory aspects for a wide range of products. It was seen that thermal processing at high temperatures for increased durations affected both the physicochemical and structural properties of food. Nevertheless, novel techniques caused minimum destructive impacts as compared to the traditional processes. However, further studies applying novel roasting techniques with a wide range of operating conditions on different types of products are crucial to establish the potential of these techniques in obtaining safe, quality foods.

Combination of thermal pretreatment and alcohol-assisted aqueous processing for rapeseed oil extraction

BACKGROUND

The alcohol-assisted aqueous extraction processing (AAEP) of oil has many advantages such as no need for demulsification and relative low cost compared with enzymatic aqueous extraction processing (EAEP). Three kinds of thermal pretreatments including dry-heating, wet-heating and soak-heating followed by the AAEP of rapeseed oil were investigated.

RESULTS

Both soak-heating and wet-heating had a higher contribution rate to oil yield than dry-heating due to the enhancement of heat transfer rate owing to the high moisture content in the rapeseed cells. However, oil from soak-heated rapeseeds showed a much lower level on peroxide value (0.41 mmol kg^-1 ) than that of wet-heated rapeseeds (5.23 mmol kg^-1 ). In addition, transmission electron microscopy images illustrated that promoting effects of soak-heating and wet-heating on oil release were attributed to the coalescence of oil bodies. A relative low concentration of alcohol solution as an extraction medium, the highest oil recovery of 92.77% was achieved when ground rapeseeds (mean particle size: 21.23 µm) were treated with 45% (v/v) alcohol for 2 h at 70 °C and pH 9.0. Both the acid value and the peroxide value are lower than the commercial oil produced by extrusion and hexane extraction. Furthermore, the oil produced from AAEP also had higher content of tocopherols and lower content of trans-fatty acids than the commercial oil.

CONCLUSION

AAEP of oil from soak-heated rapeseeds is a promising alternative to conventional oil extraction methods. © 2019 Society of Chemical Industry.

Oxidative Stability of Selected Edible Oils

The aim of the study was to examine and compare oxidative stability of refined (peanut, corn, rice bran, grapeseed, and rapeseed) oils. The oils were subject a Schaal Oven Test (temperature 63 ± 1 °C) and a Rancimat test (temperature 120 °C) and their stability was compared at the 1st and 12th month of storage. Changes in the peroxide (PV) and anisidine (AnV) values in the thermostat test were the fastest in rapeseed oil and grapeseed oil. The best quality was preserved by peanut and corn oils both in the first and the twelfth month of storage. The induction times for the rice bran, corn, peanut, and rapeseed oils were similar from 4.77 h to 5.02 h in the first month and from 3.22 h to 3.77 h in the twelfth month. The shortest induction times were determined for grapeseed oil: 2.4 h and 1.6 h, respectively. A decrease of oxidative stability of about 30% was found in all the oils after 12 months of storage. The PV of 10, determined in the thermostat and Rancimat tests, were achieved at the latest in corn oil and the fastest in rice bran oil.