Improvement of the quality of parboiled rice by using anti-browning agents during parboiling process

Impact of magnetic field-assisted freezing on the physicochemical properties and starch structure of cooked rice: Effects of magnetic types, intensities, and cryostasis time

A magnetic field-assisted freezing system was developed to mitigate the degradation of taste quality in frozen cooked rice (FCR). The physicochemical properties and starch structure were analyzed under varying magnetic field types, intensities, and cryostasis time. The analysis of freezing characteristics indicated that treatments with 10 mT static magnetic fields (SMF) and 6 mT alternating magnetic fields (AMF) yielded optimal results, significantly reducing the duration of the maximum ice crystal generation zone by approximately 18 min. Compared to no magnetic field (NMF) treatment, a 16-day frozen storage experiment showed significant improvements in the texture characteristics of cooked rice treated with magnetic fields. However, the moisture content of rice treated with AMF closely resembled those of freshly cooked rice, with a slight increase in yellowness compared to SMF treatment. Throughout the storage period, the crystallinity for the AMF treatment exceeded that of the SMF treatment by 2.99 %. Furthermore, compared to SMF treatment, water molecules in FCR treated with AMF are more tightly bound. Given the superior sensory scores in the AMF treatment, it can be concluded that while SMF reduces color degradation, AMF is more effective in preserving moisture, and structural density. Hence, magnetic fields, especially AMF, emerge as a promising auxiliary technology for FCR, offering a theoretical basis for advancing cold chain logistics technology for cooked rice.

Reduced of mycotoxin levels in parboiled rice by using ozone and its effects on technological and chemical properties

Contamination of foods by mycotoxins is a reality. However, emerging technologies such as ozonization can be used to reduce the levels of these contaminants. Thus, the aim of this study was to evaluate the effects of using ozone at different period and application times during the soaking step of parboiling process. Samples were analyzed for qualitative and quantitative analysis of mycotoxins, swelling power and solubility, head rice yield, protein solubility, cooking time, texturometric profile, colorimetric profile and defective grains. The results showed tha parboiled rice grains treated with ozone present significant reduction of mycotoxins contamination, regardless of the time and period of application and the mycotoxin evaluated. Regardig to technological properties, the samples treated with ozone in the final 3 h and for 5 h of soaking presented higher head rice yield, luminosity and hardness, with decreases in cooking time, percentage of defective grains and soluble protein.

Silica Hydride: A Separation Material Every Analyst Should Know About

This review describes the development, special features and applications of silica hydride-based stationary phases for HPLC. The unique surface of this material is in contrast to ordinary, standard silica, which is the material most frequently used in modern HPLC stationary phases. The standard silica surface contains mainly silanol (Si-OH) groups, while the silica hydride surface is instead composed of silicon-hydrogen groups, which is much more stable, less reactive and delivers different chromatographic and chemical characteristics. Other aspects of this material are described for each of the different bonded moieties available commercially. Some applications for each of these column types are also presented as well as a generic model for method development on silica hydride-based stationary phases.

Color and structural modifications of alkaline extracted sunflower protein concentrates and isolates using L-cysteine and glutathione

Alkaline sunflower protein extraction can be performed along with de-phenolization of sunflower seed proteins if greening is unwanted. This greening is promoted at alkaline pH when chlorogenic acid (CGA) oxidizes and reacts with amino acids such as lysine. Thiol-containing dough conditioners: L-cysteine hydrochloride and glutathione (GSH) were investigated as an alternative de-greening strategy to acidification and de-phenolization. Greening and browning inhibition of thiols (GSH and Cysteine) were modeled by a combination of additive and interaction effects of extraction pH (7.0 to 11.0) and thiol concentration (0.00 to 5.60 mM) randomly assigned by Response Surface Methodology (RSM). The powders with the highest greening were the controls (pH 8.9-9.3 and no added thiols) and powders at pH 10.41 with 0.82 mM thiols. From RSM, the maximum greening inhibition was achieved at pH 8.71 and 4.23 mM cysteine, and pH 8.51 and 3.78 mM GSH. However, cysteine caused more browning at alkaline pH than GSH. Furthermore, fluorescence spectroscopy showed that cysteine had a protective effect against alkaline unfolding, whereas GSH quenched fluorescence in a concentration-dependent manner. Overall, de-greening of alkaline extracted sunflower protein was achieved by adding cysteine or glutathione, but the thiols differed in their contribution to the browning and unfolding effect.

The influence of processing parameters of parboiled rice on its physiochemical and texture properties

The impact of different parboiled rice process conditions on physical (whiteness and yellowness), chemical (amylose and fat contents), and texture (hardness and toughness) properties was studied. The parboiled rice was produced from the Suphanburi 1 variety. The correlation between chemical and texture properties was also analyzed. To study the effect of the soaking process, the time (2, 3, and 6 hr) and temperature (65 and 75°C) of soaking were altered, while the steaming condition was fixed at 100°C for 20 min. To study the effect of the steaming process, the soaking condition was fixed at 65°C for 6 hr while steaming condition was altered, including time (10 and 20 min) and temperature (90 and 100°C). The results show that the different conditions influenced the physical and chemical properties of parboiled rice. The amylose content was negatively correlated (Hardness, r = -0.52) (Toughness, r = -0.38) and fat content was positive low correlated (Hardness, r = 0.20) (Toughness, r = 0.12) with textural properties. Due to the specification of parboiled rice for exportation varying according to customer requirements, the results of this research provided some useful information for parboiled rice factories.

Microwave Parboiling: Reduction in Process Time, Browning of Rice and Residual Phosphorus Content in the Waste Water

The conventional prolonged parboiling process results in high operation cost and grain darkening, which may limit consumption. Moreover, residue generation by rice industries is another challenge. The objective of this study was to evaluate the use of microwave irradiation during soaking and gelatinization stages of parboiling rice. Processing time, colorimetric profile, broken and nongelatinized grains, sucrose and glucose content, free 5-hydroxymethyl-2-furfural, and residual phosphorus were evaluated. As the soaking and gelatinization times during microwave treatments increased, the colorimetric parameters increased; however, the values were lower than those with the conventional process. Regardless of soaking time, a decrease in broken and nongelatinized grains was obtained by using the lowest steaming time (5 min). Additionally, lower residual phosphorus content was found in soaking water (10 and 20 min) when using microwave irradiation. Under favorable conditions, a reduction in the levels of broken and nongelatinized grains, residual phosphorus, and color changes was observed, indicating that microwave irradiation may be more beneficial than conventional parboiling. PRACTICAL APPLICATION: Parboiling requires a high volume of water and soaking time, which leads to high costs, underutilization of infrastructures, and high residue in the water after processing. The rapid parboiling process involves the use of microwaves during the soaking and gelatinization stages. The main advantages of the microwave parboiling process include reduced processing time, ranging from 83% to 95%, higher gelatinization, greater yield, reduced darkening, and reduced residual phosphorus in the effluents by 60%. This report can aid industries in streamlining their processes, thereby providing a high-quality, lower cost, and environmentally safe product.