Effect of Cold Plasma Treatment on Cooking, Thermomechanical and Surface Structural Properties of Chinese Milled Rice

Effect of soaking in plasma-activated liquids (PALs) on heavy metals and other physicochemical properties of contaminated rice

In this study, plasma-activated liquids (PALs) were produced by a cold plasma gliding arc device at two different exposure times (7.5 and 15 min) and compared with deionized water (DW) as a control. The results showed that the amount of arsenic (As: 98 %), cadmium (Cd: 93 %), and lead (Pb: 93.3 %) were significantly decreased in all samples after soaking in PALs and DW than raw rice (p < 0.05). However, 15-min PALs were more successful. All soaked samples did not exceed the maximum residue limits (MRLs). A softer and easier chewing texture was observed for rice samples soaked in PALs than the sample soaked in DW. The samples treated with PALs also showed a lower gelatinization temperature and enthalpy. The color parameters and microstructure of rice samples were affected by treatment with PALs. Therefore, soaking rice in PALs before cooking can be considered an effective method to reduce the heavy metals in rice.

Physicochemical characterization and sensory enhancement of cold plasma treated black whole wheat flour

This study examined the effects of cold plasma (CP) treatment on the physicochemical properties and sensory quality of black whole wheat flour (BWWF). Various factors including nutrient composition, color, amino acids, aroma, particle size, microstructure, antioxidant activity, and water migration were analyzed before and after CP treatment. The findings revealed that CP treatment had a minimal impact on the baseline nutrient composition of BWWF, but significantly improved its free amino acid profile, enhancing its nutritional value. The treated BWWF had an improved surface color, appeared brighter and yellower, and gave off a pleasant mellow aroma, while removing unpleasant flavor. The total phenolic content of BWWF increased while the flavonoid and anthocyanin content decreased after the treatment. CP-treated BWWF underwent aggregation cross-linking in the microstructure, and the content of bound water decreased, but the stability increased. In conclusion, CP treatment had great potential to improve the physicochemical properties and sensory quality of BWWF.

Effect of Intermittent Low-Pressure Radiofrequency Helium Cold Plasma Treatments on Rice Gelatinization, Fatty Acid, and Hygroscopicity

To establish the safe and reproducible effects of cold plasma (CP) technology on food products, this study evaluated the gelatinization parameters, fatty acid profile, and hygroscopic properties of rice grains repeatedly treated with low-pressure radiofrequency (RF) helium CP (13.56 MHz, 140 Pa, 120 W-20s, 0-4 times, and 300 g sample). Compared with the untreated (zero times) sample, with an increase in CP treatment times from one to four on rice, the water contact angle and cooking time decreased, while the water absorption rate and freshness index increased, and the pH value remained unchanged. CP repeating treatments essentially had no effect on the gelatinization enthalpy, but significantly increased the peak temperature of gelatinization. From the pasting profile of rice that has been repeatedly CP treated, the peak, breakdown, and setback viscosities in flour paste decreased. CP repeating treatments on rice did not change the short-range molecular order of starch. Compared with the untreated sample, the first helium CP treatment maintained the content of C18:1n9c, C18:2n6c, and C18:3n3, but the second to fourth CP treatment significantly decreased contents of these fatty acids (FAs) as the C18:0 content increased. The first three CP treatments can increase the water and sucrose solvent retention capacity in rice flours. CP repeatedly treated rice first exhibits the similar monolayer water content and solid surface area of water sorption. Principal component analysis shows that contact angle, pasting parameters, and fatty acid profile in milled rice are quite sensitive to CP treatment. Results support that the effect of low-pressure RF 120W helium CP treatment 20 s on rice grains is perdurable, and the improvement of CP intermittent treatments on rice cooking and pasting properties is an added benefit, and the hygroscopic properties of rice was kept.

Cold plasma as a pre-treatment for processing improvement in food: A review

Thermal processes can be very damaging to the nutritional and sensory quality of foods. Non-thermal technologies have been applied to reduce the impact of heat on food, reducing processing time and increasing its efficiency. Among many non-thermal technologies, cold plasma is an emerging technology with several potential applications in food processing. This technique can be used to preserve and sanitize food products, and act as a pre-treatment for drying, extraction, cooking, curing, and hydrogenation of foods. Furthermore, the reacting plasma species formed during the plasma application can change positively the sensory and nutritional aspects of foods. The aim of this review is to analyze the main findings on the application of cold plasma as a pre-treatment technology to improve food processing. In its current maturity stage, the cold plasma technology is suitable for reducing drying time, increasing extraction efficiency, as well as curing meats. This technology can convert unsaturated into saturated fats, without forming trans isomers, which can be an alternative to healthier foods. Although many advantages come from cold plasma applications, this technology still has several challenges, such as the scaling up, especially in increasing productivity and treating foods with large formats. Optimization and control of the effects of plasma on nutritional and sensory quality are still under investigation. Further improvement of the technology will come with a higher knowledge of the effects of plasma on the different chemical groups present in foods, and with the development of bigger or more powerful plasma systems.

Impact of cold plasma on the biomolecules and organoleptic properties of foods: A review

Cold plasma is formed by the nonthermal ionization of gas into free electrons, ions, reactive atomic and molecular species, and ultraviolet (UV) radiation. This cold plasma can be used to alter the surface of solid and liquid foods, and it offers multiple advantages over traditional thermal treatments, such as no thermal damage and increased output variation (due to the various input parameters gas, power, plasma type, etc.). Cold plasma appears to have limited impact on the sensory and color properties, at lower power and treatment times, but there has been a statistically significant reduction in pH for most of the cold plasma treatments reviewed (p < 0.05). Carbohydrates (cross linking and glycosylation), lipids (oxidation), and proteins (secondary structure) are more significantly impacted due to cold plasma at higher intensities and longer treatment times. Although cold plasma treatments and food matrices can vary considerably, this review has identified the literary evidence of some of the influences and impacts of the vast array of cold plasma treatment parameters on the biomolecular and organoleptic properties of these foods. Due to the rapidly evolving nature of the field, we have also identified that authors prioritize the presentation of different information when publishing from different research areas. Therefore, we have proposed a number of key physical and chemical cold plasma parameters that should be considered for inclusion in all future publications in the field.