基于近红外光谱扫描技术对高粱中粗脂肪、粗纤维、粗灰分含量的测定方法研究

本试验旨在探讨利用近红外光谱扫描技术对高粱籽粒中粗脂肪、粗纤维、粗灰分进行测定的可行性。以收集的110个高粱籽粒为研究对象,采GB/T6433-2006、SN/T0800.8-1999及GB/T6438-2007对粗脂肪、粗纤维、粗灰分含量进行测定。利用傅里叶变换近红外光谱仪采集样品的近红外漫反射光谱。光谱扫描范围4000～12800 cm-1,分辨率16 cm-1,样品重复装样扫描4次,每次扫描64次获得平均光谱,取4次扫描光谱作为样本的原始光谱。根据定标集决定系数、定标集标准偏差、定标集交互验证决定系数、定标集交互验证标准误差等指标,确定最优模型。结果表明：高粱籽实中粗脂肪、粗纤维、粗灰分的近红外扫描光谱交互验证集相对分析误差分别为3.93、1.47及2.37;验证集相对分析误差分别为2.57、1.23及2.34。粗脂肪的预测模型可用于实际应用,而粗纤维和粗灰分预测模型需要进一步完善。     

Effect of formulated zimmu (Allium cepa L. × Allium sativum L.) extract in the management of grain mold of sorghum

BACKGROUND: The in vitro antifungal activity of zimmu (Allium cepa L. × Allium sativum L.) extract against Aspergillus flavus Link., Fusarium moniliforme Sheld, Curvularia lunata (Wakker) Boedijn and Alternaria alternata (Fr.) Keissler, the fungi associated with grain mold of sorghum, was evaluated. An emulsifiable concentrate (EC) formulation of zimmu extract was prepared and its efficacy in controlling grain mold was tested under field conditions. RESULTS: The leaf extract of zimmu exhibited strong antifungal activity against A. flavus, F. moniliforme, C. lunata and A. alternata and caused in vitro fungal growth inhibition of 73.3%, 71.1%, 70.0% and 74.4%, respectively. Foliar application of zimmu formulation 50 EC at 3 mLL^?1 (v/v) concentration 60, 75 and 90 days after sowing significantly reduced the incidence of grain mold and increased the grain weight and grain hardness. A significant reduction in the aflatoxin B1 content in sorghum grains was observed when sorghum plants were sprayed with zimmu formulation 50 EC at 0.3% concentration. Western blot analysis revealed that a thaumatin‐like protein (TLP) a molecular mass of 23 kDa that cross‐reacted with zeamatin antiserum was expressed at higher levels in sorghum grains after treatment with zimmu formulations. CONCLUSION: The leaf extract of zimmu exhibited antifungal activity against sorghum grain mold fungi. The formulated zimmu extract was significantly effective in reducing the grain mold incidence in sorghum under field conditions. This formulated zimmu extract offers a novel alternative for eco‐friendly management of grain mold of sorghum. Copyright © 2007 Society of Chemical Industry     

Modification of gluten-free sorghum batter and bread using maize, potato, cassava or rice starch

Gluten-free sorghum bread was made from cassava, maize, potato or rice starch and sorghum in the ratios 10:90, 20:80, 30:70, 40:60 and 50:50. The other baking ingredients, on flour-weight-basis, were water (100%), sugar (6.7%), egg white powder (6%), fat (2%), salt (1.7%) and yeast (1.5%). Increasing starch content changed the batters’ consistencies from soft doughs to thin pourable batters. Increasing starch content decreased crumb firmness and chewiness, and increased cohesiveness, springiness and resilience of all breads. Cassava-sorghum and rice-sorghum breads had better crumb properties than maize-sorghum or potato-sorghum breads. Although the crumb properties of all breads declined (i.e. firmness and chewiness increased; cohesiveness, resilience and springiness decreased) on storage, the formulation containing 50% cassava starch retained the best overall texture.     

Toxigenic molds in Tunisian and Egyptian sorghum for human consumption

The objective of this study was to characterize the mycoflora of sorghum grains commercialized in the Tunisian retail market and to identify aflatoxins (AFs), ochratoxin A (OTA) and zearalenone (ZEA) producing species. Sixty four samples of sorghum (37 samples of Tunisian sorghum and 27 samples of Egyptian sorghum) were analyzed. Dilution plating (CFU, colony forming units) was used for fungal enumeration. The isolation of mycobiota was carried out by plating of grains on PDA and malachite green medium. Aspergillus section Flavi and section Nigri and Fusarium isolates were sub-cultured in CYA to test their ability to produce AFs, OTA and ZEA, respectively. The selected Aspergillus section Flavi and section Nigri, Penicillium and Fusarium isolates were subjected to specific PCR assays using published species-specific primers. The results revealed the dominance of Fusarium (95.3%), followed by Aspergillus (87.2%) and Alternaria (81.2%) species. The fungal counts ranged from 100 to 1.3·10⁴ CFU/g for Tunisian sorghum and from 100 to 5.7·10³ CFU/g for Egyptian sorghum. Among Aspergillus section Flavi isolates identified by molecular biology, Aspergillus flavus was the most dominant (90.1%) while Aspergillus parasiticus represent 9.9% only. About Aspergillus section Nigri, results showed the dominance of Aspergillus niger aggregate species, including Aspergillus niger, Aspergillus tubingensis and other species. Among Fusarium species, Fusarium incarnatum was the most dominant in both Tunisian and Egyptian sorghum. Penicillium citrinum was the dominant Penicillium species in the studied samples. More than 890 isolates belonging to the genus Aspergillus and Fusarium were tested in order to test their capacity to produce AFs, OTA and ZEA. The percentage of mycotoxin producing isolates in Aspergillus section Flavi, A. section Nigri, and Fusarium was 30.0%, 4.6% and 11.1%, respectively.     

Fumigation trials on the application of ethyl formate to wheat, split faba beans and sorghum in small metal bins

Field trials were carried out in Australia with ethyl formate for insect control in wheat (Harden, NSW), split faba beans (Vicia faba) (Two Wells, SA) and sorghum (milo) (Warwick, Qld) in unsealed metal bins normally used to store grain on farms. Liquid ethyl formate was applied as a split dose (a first dose of 85 g t⁻¹ and after 4 h another dose of 85 g t⁻¹) to the top of the grain through a PVC probe (4 cm i.d.×1.2 m). This method of application was chosen to maintain ethyl formate concentrations below the flammability level, reduce vaporisation, maintain an effective concentration of ethyl formate for >10 h and to avoid liquid ethyl formate accumulating at the bottom of the bin. With wheat, the concentration of ethyl formate was maintained at effective levels for about 2 days, all insects at all stages were killed rapidly, and in 5-7 days the residues were reduced to natural levels without aeration. Split faba beans sorbed ethyl formate strongly, the residues persisted longer and complete insect control was achieved. Control was high but not 100% in the sorghum trials. Residues in the sorghum at 10 °C persisted significantly longer than at 20 °C. During application and fumigation, the levels of ethyl formate in the working environment did not exceed a threshold limit value (TLV) of 100 ppm. The field trials have shown that ethyl formate has good potential as a fumigant in unsealed small metal bins as it kills insects rapidly. Residues decreased to natural levels even without aeration after 7 days for wheat and sorghum and 26 days for split faba beans.     

Flavonoid composition of lemon-yellow sorghum genotypes

Flavonoid composition of lemon-yellow sorghums grown in two locations in Texas, USA was evaluated and compared with that of white and red sorghums using high performance liquid chromatography (HPLC-PDA). Sorghums from Lubbock were brighter in colour and had minimal weathering compared to those from College Station. Sorghums with red/purple secondary plant colour had the highest levels of 3-deoxyanthocyanidins (8–187 μg/g) and their levels were highest in grains from College Station (39–187 μg/g). Pericarp colour did not have any effect on 3-deoxyanthocyanidin levels (p > 0.05). The tan plant lemon-yellow sorghum Tx2953 had the highest levels of flavones (268–362 μg/g). Among the genotypes, lemon-yellow sorghums had the highest levels of flavanones (134–1780 μg/g), which are located in the pericarp and their levels were increased in the grains with a bright yellow pericarp and minimal weathering. The high flavanone levels in lemon-yellow sorghums makes this sorghum genotype a good source of those compounds.     

Investigations on winter season Sudanese sorghum cultivars: effect of sprouting on the nutritional value

Physicochemical attributes of sorghum grains of Wad Ahmed (summer season cultivar), Abu Ragaba and Abu Kunjara (winter season cultivars) were compared. Floury endosperms characterise grains of all cultivars. Grains of Abu Ragaba and Wad Ahmed are white and Abu Kunjara are coloured. Grains were sprouted for 24, 48 and 72 h and changes in nutrients, tannin, phytic acid, protein digestibility and total and extractable minerals were studied. The nutrients and antinutients contents significantly (P ≤ 0.05) varied between cultivars. High tannin characterises Abu Ragaba and Wad Ahmed. In vitro protein digestibility of the cultivars is comparable. Contents and HCl‐extractability of Ca, P and Fe are varied. Abu Ragaba had the higher HCl‐extractability of the minerals. Sprouting changed contents of the nutrients, reduced significantly (P ≤ 0.05) tannins and phytic acid and increased digestible protein in all cultivars. Reduction of tannins was the highest in Abu Ragaba. The magnitude of reduction increased as sprouting prolonged.     

Flavonoid composition of red sorghum genotypes

The effect of genotype on flavonoid composition was investigated in 13 sorghum varieties using HPLC-DAD. Sorghums with red/purple secondary plant colour had the highest levels of 3-deoxyanthocyanins (32–680 μg/g) with the black pericarp sorghums having the highest. Sorghums with red secondary plant colour had a high proportion of apigeninidin compounds (66–89%), which suggested that secondary plant colour affects 3-deoxyanthocyanin composition. Red pericarp sorghums with tan secondary plant colour had the highest levels of flavones (60–386 μg/g). Flavanones were also detected in all sorghums with a red pericarp (8–48 μg/g) and secondary plant colour did not affect their levels (p > 0.05). The elevated 3-deoxyanthocyanin levels in the black sorghums were due to their pericarp colour. Black sorghum panicles that were exposed to sunlight during their development had three times more 3-deoxyanthocyanins (617 μg/g) than those that were covered with a paper bag (212 μg/g). This study showed that flavonoid levels and composition were affected by sorghum genotype. This information will help sorghum breeders to produce sorghum genotypes with maximum levels of desired flavonoids.     

Evolution of fungal population and mycotoxins in sorghum silage

Silage, one of the most important feed sources for cattle, is vulnerable to contamination by spoilage moulds and mycotoxins because ensilage materials are excellent substrates for fungal growth. The aim of this study was to identify the mycobiota of sorghum silages, to determine the presence of aflatoxins and fumonisins, and to correlate these results with physical parameters of the silage. A total of 275 samples of sorghum were collected from dairy farms in the south-west region of Uruguay were silage practices are developed. The presence of fungi was observed in all of the sorghum samples with values varying from 0.2 × 10⁴ to 4085 × 10⁴ UFC g^?1. Significant difference were detected in the total number of fungi during the storage period; at six months there is a high risk of fungal spoilage. The most frequent genera isolated from sorghum samples were Penicillium (70%), Aspergillus (65%), Absidia (40%), Fusarium (35%), Paecilomyces (35%) and Alternaria, Cladosporium, Gliocadium and Mucor (30%). The toxigenic species most frequently found were Penicillium citrinum, Aspergillus flavus and Fusarium nygamai. Only two samples were contaminated by AFB1 with levels of 1 and 14 µg kg^–1. Fumonisin was detected in 40% of freshly harvest samples with levels ranged from 533 µg kg^–1 to 933 µg kg^–1. The use of silo bags seems to be an effective tool to store sorghum. However, the presence of toxigenic fungi show that regular screening for mycotoxins levels in silages must be performed to avoid the exposure of animals to contaminated feed and the introduction of these compounds into the food chain.     

Study of chemical compositions,anti-nutritional contents and digestibility of electron beam irradiated sorghum grains

Effects of electron beam irradiation at doses of 10, 15, 20, 25 and 30 kGy on chemical composition, phytate and tannin contents, and in vivo digestibility of sorghum grain were investigated. Irradiation had no effect (p > 0.05) on chemical compositions. Tannin content was reduced (p < 0.05) by 28%, 30%, 42%, 83% and 86% and phytate content reduced (p < 0.05) by 39%, 49%, 66%, 79% and 90% in electron beam irradiated compared to control, respectively. Irradiation improved (p < 0.05) in vivo digestibilities of dry matter, crude protein, true protein and gross energy. Based upon these results, electron beam irradiation was judged to be a useful processing method for reducing the anti-nutritional compounds and therefore, improving nutritive value of sorghum grain.     

Structural characteristics of sorghum kernel: Effects of temperature

In this study, the effect of cold water, hot water, and steam tempering on sorghum kernel physical and mechanical properties was studied. Single kernel characteristics (SKCS), abrasive hardness, structural changes, and texture of kernels were evaluated as an effect of temperature. At the same moisture level, cold water tempered sorghum had both higher SKCS hardness and abrasive hardness than hot water and steam tempered sorghum kernels. The increase in abrasive hardness, SKCS-hardness index was highly correlated with the moisture content of kernel. The abrasive hardness index, which represents the pericarp properties, did not show any correlation with moisture content but had correlation to the structural changes. The SEM images indicated the structural changes in pericarp after hot water and steam treatment. Steam tempering methods made the pericarp tougher than the cold water and hot water tempering methods and, meanwhile, softened the endosperm by adding moisture to the kernel.     

高粱中酚类物质及其功能活性的研究进展

随着生活质量的提高,人们越来越重视健康饮食,高粱等杂粮因其独特的植物化学成分而备受消费者的喜爱。本文主要对高粱作为我国乃至世界上一种重要的耐早粮食作物其含有的原花青素、酚酸、花青素、黄酮等酚类物质的化学结构与分类、提取方法及潜在的保健功能等方面进行了阐述。自由基损伤会引起脂质、DNA、蛋白质、细胞膜等体内大分子损伤,是多种疾病,例如老化、癌症、心血管疾病等的诱因。高粱富含多种植物化学成分,大量研究表明高粱中的这些酚类物质具有抗氧化能力与自由基清除能力。适当补充外源抗氧化剂以改善衰老以及减少疾病的发生已成为目前消费者重点关注的问题,因而高粱作为一种健康食品具有广阔的应用与开发前景。     

Differential response of ducks and chicks to dietary sorghum tannins

White Pekin ducklings were reared in floor pens and given access to nipple-type waterers in order to eliminate a feeding behaviour previously observed in battery brooder-raised ducks in which sorghum tannins were possibly detoxicated by exposure of the ground grain to water. High-tannin sorghum (HTS)—soya bean meal and low-tannin sorghum (LTS)—soya bean meal diets, suboptimal in protein, with or without supplemental methionine, and either in dry mash or pellet form, were fed to both day-old ducks and chicks for either 14 or 17 days, respectively. The chicks were reared in battery brooders. In contrast to previous findings with ducks raised in battery brooders, HTS-fed ducks reared in floor pens exhibited reduced weight gain and feed efficiency values compared with LTS-fed ducks. However, the magnitude of the growth depression caused by feeding ducks HTS versus LTS was much less than that observed in chicks fed the identical diets (17 versus 33%, respectively). Methionine supplementation of the HTS diets completely overcame the reduced weight gain in ducks, but feed efficiency values were still significantly poorer than those of ducks fed methionine-supplemented LTS diets. In contrast, although HTS-fed chicks responded to dietary methionine supplementation, they still exhibited poorer weight gain and feed eficiency values compared with birds fed LTS diets similarly supplemneted. Increasing the dietary level of supplemental methionine did not result in any further improvement in performance of chicks fed either LTS- or HTS-based diets. It was concluded that, compared with chicken, ducks are less affected by dietary sorghum tannins.     

Influence of grain germination on functional properties of sorghum flour

A Sudanese sorghum cultivar (Fetarita) was germinated for five days and protease and amylase activities were measured every 24 h. Results showed that flour obtained from the 3rd germinated sorghum grain had high protease and amylase activities. The functional properties of flours derived from the germinated sorghum seeds were studied and ungerminated seeds were used as a control. Germinated samples had a higher protein solubility compared with the control, and the highest solubility occurred at pH 6. Germination also increased the protein solubility index of sorghum flour. Germinated sorghum flour had a least gelation concentration of 8% compared with 18% for the control. The bulk densities of germinated flours were lower compared to the ungerminated one. Water and oil capacities were increased by germination from 131.34% and 90.56% to 141.64% and 108%, respectively after three days of germination. The emulsifying activities and stabilities of the germinated samples increased significantly. In addition, germination improved the foamability of sorghum flour from unfoam flour to a flour with foam after three days of germination; and the foaming capacity and stability increased significantly with increasing germination time. Thus, the study indicated that germination improved the functional properties of sorghum and it would be possible to design new foods using germinated sorghum.     

发芽白高粱的工艺优化及主要营养成分分析

为提高营养价值、改善食用品质,拓宽白高粱在食品工业中的用途,本研究对白高粱的发芽工艺进行了优化、对发芽前后主要营养成分和感官品质进行了分析。单因素试验和响应面法优化的结果表明,1.0%的次氯酸钠溶液消毒10 min,浸种19 h,发芽温度30℃,白高粱的发芽率可达92%以上。分析发芽0~120 h的主要营养成分变化,发现随着发芽时间的延长,白高粱的水分含量显著增加、淀粉和灰分含量显著降低,蛋白质和脂肪含量无显著变化,但氨基酸总量增幅达到9.4%~19.2%、Lys含量增幅在发芽第72 h达最高34.7%,Cys-s含量在开始发芽后降低了一个数量级;单宁未检出,感官评定发现涩味消失。结果表明,发芽可以改善白高粱的食用品质和加工品质。     

Development of Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) on sorghum milling fractions

A series of tests was conducted to determine if Tribolium castaneum (Herbst), the red flour beetle, could survive on six milled sorghum fractions: Bran, Coarse Grits, Fine Grits, Flour, Red Dogs, and Shorts. In the first test, parental adults were exposed on the fractions, removed, and then the fractions were held for six-seven weeks at 27 °C. Late instar larvae and progeny adults were present in all fractions. In the second test, at least 80% of single neonates (1-2-day-old larvae) held on 1 g of a fraction at 27 °C for seven weeks were able to complete development to the adult stage. In the final test, individual neonates were held on 1 g of a fraction at 37 °C, 32 °C, 27 °C, or 22 °C. Time to adult emergence at each temperature ranged from 17 to 23 days, 21–27 days, 28–50 days, and 67–113 days, respectively, depending on the specific fraction. Logistic functions were compared for mean developmental times for each temperature-fraction combination. The six fractions were also analyzed for ash, fat, fiber, moisture, protein, and starch content. The fractions varied with respect to these chemical constituents; fat and moisture content were negatively correlated with development in some comparisons, though overall there was no correlation between these chemical components and neonate development on the fractions. Temperature had an obvious effect on neonate development, which has implications for assessing risk of pest infestations inside sorghum mills during warmer months of the calendar year. In addition, T. castaneum will reproduce and develop on all of the sorghum fractions included in this study, which are commonly generated during the sorghum milling process. Sanitation and removal of residual materials such as the measured fractions could also help with overall pest management of T. castaneum.     

Comparative antioxidant, antiproliferative and phase II enzyme inducing potential of sorghum (Sorghum bicolor) varieties

Epidemiological evidence has linked consumption of sorghum with reduced incidences of gastrointestinal cancer, especially cancer of esophagus. No information is available on how sorghum may effect the chemoprotective properties. We investigated in vitro potential of eight sorghum varieties to induce phase II detoxifying enzymes using the NAD(P)H:quinone oxidoreductase (NQO) enzyme assay, and also inhibit proliferation of esophageal, OE33, and colon, HT-29, carcinoma cells using the PicoGreen and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays; these properties were compared to phenolic profile and antioxidant activity of the sorghum. Black sorghum extract high in 3-deoxyanthocyanins was the most potent NQO inducer, doubling NQO activity at 5.0 μg/mL and maximally inducing the enzyme activity by 3.0 times. White sorghum was a moderately strong inducer, maximally increasing NQO activity by 80%; tannin-containing sorghums were non-inducers. On the other hand, the tannin-containing sorghum extracts had strongest antiproliferative activity against both OE33 and HT-29 cells (IC₅₀, 38-105 μg/mL); the white sorghum extract was the least potent (IC₅₀, 389->800 μg/mL). Antiproliferative activity correlated with antioxidant activity whereas NQO-inducer capacity did not. Sorghum extracts have strong chemoprotective potential which is partially independent of their antioxidant properties. They may thus be valuable health-promoting ingredients in whole-grain based products.     

Effect of heat treatment of sorghum grains on storage stability of flour

Sorghum flour is susceptible to rancidity and develops off-flavor within a short duration when stored. Heat treatment on the development of rancidity after long-term storage of flour was studied. Heat treatment varying in severity was applied to the whole grains of different varieties of sorghum viz., CSH-9, CSH-5, M35-1 and a local variety varying in their morphological features. A trend was seen that when the thermal duration was for a shorter time, the shorter was the storage duration in certain varieties. Exposure of grains to moist heat for 15 min retarded hydrolytic rancidity significantly (p < 0.05) in CSH-5 until 6 months of storage and in the remaining varieties until 8 months of storage, Heat application for 15 min retarded the development of rancidity irrespective of the morphological variations and the oil content. Lipase activity varied among the varieties with CSH-5 recording higher activity when compared to the other varieties. No major differences in the physicochemical properties were observed in flours from 15 min heat-processed grains when compared to flours from unprocessed grains.