Grain Oil Science and Technology最新文献

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.

Due to its high nutritional and dietotherapy values, highland barley has attracted the attention and favor of people all over the world in recent years. It has been demonstrated that the nutritional components of highland barley are comprehensive and unique, with the characteristics of high protein, high fiber, high vitamin, low fat, low sugar and variety of bioactive components. As the most important component in highland barley, highland barley starch not only has low digestibility, but also has good freeze-thaw stability, high solubility, good emulsion stability and superior film forming performance, which makes it have great application value in food, medicine and industrial production. The content of highland barley protein, which is rich in 18 kinds of amino acids, is higher than that of most grains, and its derivatives play an important role in medical treatment. Unfortunately, highland barley protein cannot form gluten network structure, which limits the application in daily staple food to a certain extent. Highland barley also contains a large amount of dietary fiber, especially β-glucan. Long-term consumption could significantly reduce the incidence of chronic diseases and metabolic syndromes such as heart disease and diabetes. However, the research on the application of highland barley is still in the laboratory stage, which failed to achieve large-scale application in the actual production. The value of highland barley has not been brought into full play, which leads to the waste of its resources and the reduction of its added value. This paper reviewed the macronutrients, health functions and applications of highland barley, aiming to provide some reference for the development of highland barley in food and health industry.

As a non-thermal processing technology, high hydrostatic pressure (HHP) can be used for starch modification without affecting the quality and flavour constituents. The effect of HHP on starch is closely related to the treatment time of HHP. In this paper, we investigated the impacts of HHP treatment time (0, 5, 10, 15, 20, 25, 30 min) on the microstructure, gelatinization and thermal properties as well as in vitro digestibility of oat starch by scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, ¹³C NMR and differential scanning calorimeter. Results showed that 5-min HHP treatment led to deformation and decreases in short-range ordered and double-helix structures of oat starch granules, and further extending the treatment time to 15 min or above caused the formation of a gelatinous connection zone, increase of particle size, disintegration of short-range ordered and double-helix structures, and crystal structure change from A type to V type, indicating gelatinization occurred. Longer treatment time also resulted in the reduction in both the viscosity and the stability of oat starch. These indicated that HHP treatment time greatly influenced the microstructure of oat starch, and the oat starch experienced crystalline destruction (5 min), crystalline disintegration (15 min) and gelatinization (> 15 min) during HHP treatment. Results of in vitro digestibility showed that the rapidly digestible starch (RDS) content declined first after treatment for 5 to 10 min then rose with the time extending from 15 to 30 min, indicating that longer pressure treatment time was unfavourable to the health benefits of oat starch for humans with diabetes and cardiovascular disease. Therefore, the 500-MPa treatment time for oat starch is recommended not more than 15 min. This study provides theoretical guidance for the application of HHP technology in starch modification and development of health foods.

Fusarium moniliforme (F. moniliforme) and its secondary metabolite fumonisin pose a severe threat to food safety, and searching for effective antimicrobial agents is a focus of current research. In this study, the secondary structure of Sub3 was analyzed by circular dichroism, meanwhile, the inhibition rate of Sub3 against spores, mycelia of F. moniliforme and infected maize was studied. To explore the possible inhibition mechanisms, morphological and structural changes of spores treated with Sub3 at 0, 1/2MIC (minimum inhibitory concentration) and MIC were observed by scanning electron microscopy and transmission electron microscopy; the cell wall integrity, membrane integrity, reactive oxygen species, mitochondrial membrane potential, ATP synthase activity, redox reactions, and the nuclear damage of F. moniliforme were also investigated. The results showed that Sub3 was mostly in the state of random in deionized water, while mainly showed the β-sheet structure in the hydrophobic environment of 50% Trifluoroethanol (TFE) solution, indicating that Sub3 might generate partial structure deformation when acting on the cell membrane; and its MIC on F. moniliforme spores was 0.2 g/L. Under the 1/2MIC and MIC, the inhibition rates of Sub3 against F. moniliforme infected maize were 34.3% and 75.6%, respectively. The results of inhibition mechanisms revealed that the defective pathogenicity of F. moniliforme caused by Sub3 was attributed to damages on both the cell wall and the cell membrane, which might upset balance of intracellular redox system and mitochondrial energy metabolism and trigger nucleus damage, ultimately leading to cell death. Meanwhile, Sub3 could diminished ATP synthase enzyme activity in a dose-dependent manner. The results provided direct evidence for inhibition of F. moniliforme infection of maize by Sub3, and useful knowledge applicable for food preservation.

Wheat quality detection is essential to ensure the safety of wheat circulation and storage. The traditional wheat quality detection methods mainly include artificial sensory evaluation and physicochemical index analysis, which are difficult to meet the requirements for high accuracy and efficiency in modern wheat quality detection due to the disadvantages of subjectivity, destruction of sample integrity and low efficiency. With the rapid development of optical technology, various optical-based methods, using near-infrared spectroscopy technology, hyperspectral imaging technology and terahertz, etc., have been proposed for wheat quality detection. These methods have the characteristics of non-destructiveness and high efficiency which make them popular in wheat quality detection in recent years. In this paper, various state-of-the-art optical-based techniques of wheat quality detection are analyzed and summarized in detail. Firstly, the principle and process of common optical non-destructive detection methods for wheat quality are introduced. Then, the optical techniques used in these detection methods are divided into seven categories, and the comparison of these technologies and their advantages and disadvantages are further discussed. It shows that terahertz technology is regarded as the most promising wheat quality detection method compared with other optical detection technologies, because it can not only detect most types of wheat deterioration, but also has higher accuracy and efficiency. Finally, the research of optical technology in wheat quality detection is prospected. The future research of optical technology-based wheat quality detection mainly includes the construction of wheat quality optical detection standardization database, the fusion of multiple optical detection technologies and multiple quality index information, the improvement of the anti-interference of optical technology and the industrialization of optical inspection technology for wheat quality. These studies are of great significance to improve the detection technology of wheat and ensure the storage safety of wheat in the future.

Sourdough starters for making traditional steamed bread are rich in microbes. Studies have shown that, in addition to yeast and lactic acid bacteria (LAB), acetic acid bacteria (AAB) are other functional species in sourdough, but the influences of AAB on the properties of sourdough and steamed bread were rarely reported. This study aimed to assess the effects of a selected strain of acetic acid bacterium on the properties of sourdough and steamed bread. Sourdoughs and steamed breads were prepared from five different starter cultures, marked as CK (control check, with no starters), Y (only yeast), YL (yeast+LAB), YA (yeast+AAB) and YLA (yeast+LAB+AAB), and their properties were determined. The results of sourdough properties showed that the YLA sourdough had the highest total titratable acid of 14.6 mL and the lowest pH of 3.87 compared with the other groups after fermentation to 8 h; and the YLA sourdough had the greatest elasticity and viscosity. The results of quality properties of steamed bread revealed that the L* value (88.40 ± 0.09) of the YA steamed bread was significantly higher than those of the YLA and YL steamed breads; the YLA steamed bread had the highest specific volume and the highest sensory score of 89.6 ± 3.31 in comparison to those of the other groups; the hardness and chewiness of YLA and YA steamed breads were significantly lower than those of the other groups. Volatile compounds in the steamed breads were also determined by SPME–GC–MS. A total of 42 flavor substances were detected, including 3 kinds of alcohols, 8 kinds of aldehydes, 7 kinds of ketones, 2 kinds of acids, 15 kinds of esters, 1 furan, and 6 kinds of other types of compounds, mainly alkanes and esters, followed by alcohols and aldehydes. The YLA steamed bread was richer in esters, aldehydes, and acids than those from the other treatment groups. By contrast, alkanes and aldehydes were dominant in the Y and YL steamed breads. Therefore, the flavor and quality of the steamed bread made from the YLA sourdough could be improved obviously. These results could provide references for the application of AAB in dough fermentation and the improvement of new kinds of starters.

Much recent researches have demonstrated that the quality of freshly-harvested wheat could be improved during postharvest maturation by determinating the rheological properties. However, this process is time-consuming and complex. This study aimed to provide a rapid and convenient method for predicting wheat quality during postharvest maturation by use of GlutoPeak device. Farinograph and Extensograph were used to determine the rheological properties of four wheat samples (WT1, WT2, WT3, WT4) stored under different conditions (WT1: 15 °C, 50% RH; WT2: 20 °C 65% RH; WT3: 28 °C 75% RH; WT4: 35 °C 85% RH) for a total of 10 weeks, and GlutoPeak test was used to determine the gluten aggregation properties of the four samples. Correlation analysis was also conducted between the rheological properties and the gluten aggregation properties. Results of rheological properties showed that all Extensographic properties (dough extensibility, resistance, maximum resistance and area) of the four samples increased along with the storage time, and the Farinographic properties (water absorption, dough development time, dough stability time, and farinograph quality number (FQN)) had the same tendency, indicating that the rheological properties were improved considerably with storage time extending. The GlutoPeak curves revealed that Peak Maximum Time (PMT), Brabender Equivalents Maximum (BEM) and Energy to Maximum Torque (EnMT) of wheat flour of the four samples varied greatly, particularly the PMT and EnMT of the samples WT3 and WT4 increased remarkably. Results of correlation analysis showed that EnMT had significant correlation with water absorption and area (P < 0.05) for sample WT1, and also showed significant correlation with dough development time (P < 0.05) for sample WT2. For sample WT3, PMT was significantly correlated with the dough development time, extensibility, area (P < 0.05), and FQN (P < 0.01); and EnMT was in significant correction with water absorption (P < 0.01), and dough stability time, FQN, extensibility, maximum resistance and area (P < 0.05). For sample WT4, both PMT and EnMT had significant correction with area (P < 0.05). The study indicated that the GlutoPeak test is effective in quality prediction for the freshly-harvested wheat during postharvest maturation, making it possible to realize rapid wheat quality detection and evaluation in storage period.

In order to understand more clearly the morphology of the structural layers of the soft and hard wheat bran to understand the effect of mechanical force on the wheat grain, we observed the microstructure of each layer of the wheat bran from soft and hard mature wheat. Based on the differences in mechanical properties and water permeability of each wheat bran layer, the mature wheat grains were alternately treated under cold and heat conditions and separated by manual dissection. The microstructure of each layer of wheat bran from soft and hard mature wheat was determined by optical and fluorescence microscopy. Seven different structure layers were observed by optical microscopy, named them as epidermis, epicarp, cross cells, tube cells, testa, nucellar layer, and aleurone layer. All the layers of the outer bran of wheat grains were separated, except for the tube cells layer. The autofluorescence imagings of five layers were obtained. It was found that the morphology of the structural layers of the soft and hard wheat bran did not differ much, except for the aleurone layer. The aleurone layer of soft wheat bran was significantly different from that of the hard wheat bran, which is fuller and denser compared to soft wheat. In this study, more aleurone grains were lost in the aleurone layer obtained by the outside-in peeling method. The mastery of the morphology of each structural layer of the bran helps us to quickly quantify the degree of peeling of wheat milling, and to make immediate adjustments to the process. At the same time, we understand that the contents of the aleurone cells have different binding strengths with the nucellar layer and the starchy endosperm. The paper is instructive to deep investigation of wheat milling mechanism and product process refinement.