Grain Oil Science and Technology最新文献

Trans-4-hydroxy-2-hexenal (4-HHE) and trans-4-hydroxy-2-nonenal (4-HNE) are secondary lipid peroxidation products in edible oils, which are cytotoxic and genotoxic. They could covalently bind with protein, phospholipids and DNA, further disrupting the normal function of liver, lung and brain. Derivation process was generally conducted during pretreatment before detection and quantification of 4-HHE and 4-HNE. However, the derivation procedures were time consuming and chemical degradation may occur during the process. Hence, this paper aims to establish a simple solid phase extraction-high performance liquid chromatography (SPE-HPLC) method to determine the 4-HHE and 4-HNE contents in thermally treated soybean oil. C18 solid phase extraction was applied in the pretreatment process. Firstly, the reliability of the method was evaluated. Good linearity was observed in the range of 0.1–0.5 μg/mL and 0.5–10 μg/mL for 4-HHE and 4-HNE. The limit of detection (LOD) of 4-HHE and 4-HNE were 0.0486 and 0.0129 μg/mL, respectively. And the limit of quantitation (LOQ) of 4-HHE and 4-HNE were 0.1458 and 0.0431 μg/mL, respectively. Recovery rate were in the range of 89.11%–91.58% and 71.83%–79.40% for 4-HHE and 4-HNE, respectively. The method achieved the extraction, purification and detection of 4-HHE and 4-HNE simultaneously and had the advantages of simple operation, effectiveness, high precision, good repeatability. Then, the method was applied to monitor the concentrations of 4-HHE and 4-HNE in soybean oil heated at 180 °C for 40 h. The contents of 4-HHE and 4-HNE were 0–0.32 μg/g and 0–6.97 μg/g, respectively, which provided guidance for evaluating health risks of thermally treated soybean oil during heating.

Foxtail millet, originated from China and now cultivated worldwide, is a kind of high dietary fiber whole grain food, and has a high level of vitamins and proteins. Furthermore, foxtail millet has many positive effects on the adjuvant treatment of diabetes, cancer, and cardiovascular diseases because of the abundance in polyphenols. Nonetheless, foxtail millet has poor processing characteristics due to the absence of gluten, restricting the development of foxtail millet products. Studies have demonstrated that heat-moisture treatment, extrusion, superfine grinding, and microbial fermentation are promising methods to improve the processing qualities of foxtail millet. Heat-moisture treatment is helpful to increase the content of resistant starch but has less influence on other components, further reduce the GI value of foxtail millet. The extrusion has positive effects on improving the solubility of foxtail millet starch and increasing the contents of polyunsaturated fatty acid, linoleic and linolenic acids, and adverse effects on reducing the solubility of foxtail millet proteins and causing losses of nutrients due to Maillard reaction. Superfine grinding can reduce the particle size of foxtail millet to obtain a better mouthfeel of foxtail millet products. The superfine foxtail millet flour has better solubility, higher freeze-thaw stability, and lower gelatinization temperature. Microbial fermentation contributes positively to reducing the molecular weight and retrogradation value of foxtail millet starch, degrading rapidly digested starch, and improving the digestibility of foxtail millet protein. This paper briefly introduced the effects of different processing methods on foxtail millet nutrients, aiming to provide references for increasing the variety and improving the quality of foxtail millet products.

Phytosterols have received extensive attention owing to their excellent cholesterol-lowering activity and the role in cardiovascular diseases prevention. However, poor solubility in both oil and water limited the application of free phytosterols in the food industry. Chemical or enzymatic modifications were effective to improve the physicochemical properties as well as the bioavailability and cholesterol-lowering activity of phytosterols. Higher oil solubility and lower melting point of phytosterols have been achieved by esterification and transesterification with fatty acids and triacylglycerols so as to enhance the bioavailability, reduce formation of precipitates, and improve the sensory quality of products. While the researches on the improvement on its water solubility is a hot topic. Hydrophilic phytosterol derivatives have promising applications in the food industry because most of foods belong to aqueous matrix. Hydrophilic modification is useful and meaningful for phytosterols in both industrial and commercial applications. This review mainly highlights the hydrophilic phytosterol derivatives in the following aspects: (i) hydrophilic modifications of phytosterols by coupling with various polar components; (ii) cholesterol-lowering activity and possible molecular mechanisms of hydrophilic phytosterol derivatives on reducing serum cholesterol level; and (iii) safety evaluation of hydrophilic phytosterol derivatives in cell-culture studies, animal models and clinical trials.

Butyl hydroxyanisole (BHA) is usually blended with other synthetic antioxidants to improve the antioxidative property due to synergistic antioxidation. However, the synergistic antioxidation mechanisms of BHA with synergists have not been revealed yet. Thus, the antioxidation of BHA with butylated hydroxytoluene (BHT), tert-butylhydroquinone (TBHQ), or propyl gallate (PG) was investigated in the 2,2-azobis(2-amidino-propane) dihydrochloride oxidizing system. The contents of BHA, BHT, TBHQ, PG, and transformation products were measured by high-performance liquid chromatography. Transformation products were identified with liquid chromatography-mass spectrometry and gas chromatography–mass spectrometry. Results showed that synergistic antioxidation occurred between BHA and BHT, TBHQ, or PG. The synergistic antioxidation effect of BHA and BHT was attributed to the regeneration of BHA by BHT. Transformation products of BHA and BHT (compounds 6 and 7, dimers of BHA and BHT) had little contribution due to the relatively low content (<0.6%). The synergistic antioxidation effect of BHA and TBHQ or BHA and PG was attributed to the protective mechanism of TBHQ or PG on BHA. No transformation products were detected of BHA and TBHQ. Transformation products of BHA and PG (compounds 9 and 10, dimers of BHA and PG) had limited contribution due to the relatively low percentage (<7%). Therefore, BHA and BHT performed competitive antioxidation, while BHA and TBHQ or PG performed protective antioxidation.

Starch is the most abundant organic compound in nature, second only to cellulose. However, the conserved structure of native starches limits their properties and applications. Therefore, it is often necessary to modify them to obtain specific properties. As a common green and safe physical modification method, pre-gelatinization can improve the cold water solubility and swelling power of starch. The typical preparation methods of pre-gelatinized starch include spray drying, extrusion, and drum drying. Spray-dried pre-gelatinized starch still had good granule shape, but the increase of cold water solubility and cold paste viscosity was relatively small. Extruded and drum-dried pre-gelatinized starch showed serious structure destruction, significant increases in cold water solubility and cold paste viscosity, but relatively low hot paste viscosity. The properties of pre-gelatinized starch obtained by different methods are different, so do their effects on the quality of flour products. Wheat flour products, as one of the leading staple food for the people all over the world, play a vital role in people's daily life. With the improvement of people's living standards, more and more special flour products with unique features have received attentions of consumers and researchers. However, the sensory characteristics of special flour products are often inferior to traditional flour products, which limits its development. The unique functional characteristics of pre-gelatinized starch make it expected to play an essential role in the quality improvement of featured flour products. In this paper, the granule morphology, crystal structure, hydration and gelatinization properties of pre-gelatinized starch prepared by three common methods and their application in flour products were reviewed, which provides a theoretical basis for the application of pre-gelatinized starch in food industry.

Vitamin C (VC) can greatly enhance the quality properties of dough and steamed bread in the food field. However, there are few studies on the interaction between VC and gluten, and the mechanism of VC influencing the foaming capacity, emulsifiablity, and dynamic viscosity of gluten is not clear. In this study, different content of VC (0, 1%, 2%, 3%, 4% and 5%) was added to gluten to obtain VC-gluten dough samples (CK, GV1, GV2, GV3, GV4 and GV5), and the properties of the VC-gluten dough were determined. Results showed that the increasing VC content lead to increase in the content of high-, medium- and low-molecular weight gluten, suggesting that VC improved the protein solubility of gluten. The G' and G" values of dough containing VC were higher than those of the control with the increase of scanning frequency. The foaming ability of gluten increased with the increase of VC content. Emulsibility of the dough of GV1 to GV 5 were significantly lower than that of the CK. Furthermore, VC could reduce the number of bubbles in gluten protein, when the VC content was less than 3%. In conclusion, VC might reduce the emulsifying characteristic and emulsifying stability of gluten, increase the solubility of gluten, and improve the dynamic viscosity of gluten dough by changing the content of disulfide bond in gluten. This study hopes to not only improve the functional characteristics of gluten protein, but also provide the basis for future development and improvement of VC-enriched health foods.

Xylooligosaccharides (XOS) are mainly derived from lignocellulosic materials, such as rice husk, corn cobs, straw, wheat bran, wheat straw and other grain by-products. XOS have become one of the functional oligosaccharides of great concern at home and abroad due to their beneficial functional properties, such as low calorie, high stability, poor digestibility and high performance in proliferating probiotics. At present, the XOS extraction methods from grain byproducts mainly include autohydrolysis, acidolysis and enzymolysis. Among them, autohydrolysis has high requirements for equipment for achieving higher extraction rate and higher purity of products; and acidolysis can cause environmental pollution due to the usage of harmful reagents. Enzymolysis is the most common method for the production of XOS because of its high convenience, high efficiency and no pollution; and the widely used enzyme is the xylanase from Aspergillus niger. Current researches have showed that XOS can be utilized by probiotics such as Bifidobacteria and Lactobacillus to exert prebiotic effects, such as optimizing intestinal flora, promoting intestinal health, improving intestinal barrier, enhancing immune function, improving antioxidant capacity and so on. However, XOS extracted from the grain by-products contain a large amount of impurities, which limits their industrial application and makes it difficult to control the product quality. Therefore, XOS refining, separation and purification has become the key to their subsequent industrial application. This paper reviewed the current status of XOS extraction technologies from various grain by-products, and also summarized the prebiotic effect of XOS to provide reference for industrial production of XOS and its wide application in prebiotics market, thereby facilitating utilization and development of grain byproducts.

Whole wheat bread is widely available worldwide, but it is always associated with less desirable dough processibility, small loaf volume, firm and gritty texture, and other distinctive attributes compared to white bread. Emulsifiers are commonly used to improve dough handling and baking quality during bread production. In present study, five emulsifiers (diacetyl tartaric acid esters of mono- and di-glycerides (DATEM), polysorbate 80, sodium stearoyl lactylate (SSL), soy lecithin, and sucrose esters) were added during dough preparation of the whole wheat flour at 0.2%, 0.5%, and 1.0% (flour weight basis). Dough rheological behavior and bread quality attributes, such as specific loaf volume and hardness, were measured. The results showed that DATEM, sucrose esters, and SSL increased the resistance to extension of the dough, whereas soy lecithin and polysorbate 80 increased the extensibility. Soy lecithin and polysorbate 80 were the only emulsifiers that significantly increased loaf volume compared to the control. Adding higher levels (1.0%) of sucrose esters, polysorbate 80, and SSL increased the formation of amylose-lipid complex and mitigate the crumb staling during storage. The results suggested that the emulsifiers could be applied to contribute to optimum functional quality of whole wheat bread.

Flavored vegetable oils have attracted more and more attentions from consumers and researchers due to their high oxidative stability and sensory quality. In the present study, the quality indices, chemical composition and frying performance of galangal flavored sunflower oil prepared by infusion method (GFSO-I), combination pressing method (GFSO-C) and direct addition method (GFSO-A) were investigated. The results displayed that the preparation time, the levels for the acid value (AV), peroxide value (PV), p-anisidine value (AnV), total oxidation value (TOTOX), and the values for total polar compounds (TPC), thiobarbituric acid (TBA), K₂₃₂ and K₂₆₈ of GFSO-C were prominently low (P < 0.05), compared with that of GFSO-I and GFSO-A, while the fatty acid composition of them were similar. In the frying of Chinese Maye (tradional Chinese food, fried dough stick) at 180 °C for 30 h, the values for TPC, TBA, K₂₃₂ and K₂₆₈, polymer, viscosity and b* of GFSO-C were obviously low (P < 0.05), while the value for L* was obviously high (P < 0.05), compared with that of GFSO-I and GFSO-A. In the sensory evaluation, the flavor, taste, crispness and overall acceptance of Chinese Maye fried by GFSO-C were better than that of Chinese Maye fried by GFSO-I and GFSO-A. Consequently, GFSO-C is more suitable for cooking, and the combination pressing method is optimal for industrial production of GFSO.