Evaluation of selected food attributes of four advanced lines of ungerminated and germinated Nigerian cowpea (Vigna unguiculata (L.) Walp.)

The chemical composition and functional properties of ungerminated and germinated seeds of four advanced lines of cowpeas (IT81D-699, IT82E-18, IT84S-2246-4 and TVx 3236) were investigated. Ungerminated seeds contained 20.1 to 25.8% crude protein, 2.0 to 2.2% lipid, 115.1 to 210.0 mg phyticacid/100 g and 8.9 to 9.6 mg iron/100 g. The polyphenol contents of the brown- and cream-colored beans were similar (192.0 to 196.0 mg/100 g) but were significantly (p<0.05) higher than the amount (99.8 mg/100 g) found in the white beans. Germination increased the crude protein content, total phosphorus content, nitrogen solubility, fat absorption capacity and foam capacity but decreased ether extract, polyphenol and phytic acid contents, water absorption capacity, bulk density and foam stability of all cowpea lines. Incorporation of up to 0.2 M NaCI improved foam volume. Ungerminated seeds had high water (2.3–3.2 g/g) absorption capacities, while germinated seeds had high fat (3.1–3.6 g/g) absorption capacities. TVx 3236 and IT81D-699 might be selected for combining such characteristics as high crude protein, low phytic acid content and good foaming properties into a single cowpea line through breeding.     

Changes induced by infestation on some chemical properties of cowpea seeds

Three cowpea varieties were used in the present study,Insect susceptible popular variety, `Ife-brown' (IFB), an improved varietyfor insect resistance IT 81D-975 (1975) and a local black cowpea varietywith a white hilium adapted to diverse habitats, `Akidi' (AKD).Cowpea seeds were infested with Callosobruchus maculatus. Crudeprotein content of infested and uninfested whole cowpea flour and proteinconcentrate was determined. Prolamin contents of flour and proteinconcentrates were evaluated. Fat content, free fatty acid and peroxidevalues of cowpea seeds were also determined. All determinations werecarried out in infested and uninfested cowpea seeds in 3 replicates for eachdetermination. Emulsion properties of cowpea seeds stored in 3 containers,plastic cans (PC) and polyethylene bags (white and black WPB/BPB) weremonitored on a biweekly basis for 24 weeks.Varietal differences existed in the protein, fat and prolamin contents ofcowpeas. Infestation reduced the contents of these nutrients in all cases. Free fatty acid contents and peroxide values were increased by >100%. Infestation reduced the prolamin content by > 25% inall cases. Varietal differences also existed in emulsion capacities of cowpeaflours; IFB and 975 formed better and more stable emulsions than AKDflour. Storage in plastic cans led to better retention of the emulsionproperties of the cowpeas.     

Proximate Composition and Functional Properties of Fullfat and Defatted Beniseed (Sesamum Indicum L.) Flour

The proximate composition and functional properties of fullfat and defatted beniseed (Sesamum indicum L.) flour were evaluated. Functional properties studied were foam capacity and stability, water and oil absorption, bulk density, emulsion capacity and nitrogen solubility. Defatting increased the crude protein, ash, crude fiber, carbohydrate and mineral contents. Defatted flour showed comparatively better foam capacity and stability, water absorption and emulsion capacities but diminished bulk density and oil absorption capacity. Nitrogen solubility was pH dependent with a minimum at pH 4 and maximum at pH 8. Maximum nitrogen solubility (95%) was recorded for defatted flour while that for the fullfat flour was 60%. The proximate composition and functional properties of the samples suggest that beniseed flour would have useful application in fabricated foods.     

Protein quality of raw and autoclaved cowpeas: Comparison between some insect resistant and susceptible varieties

A comparative study was conducted with four improved cowpea (2 pod bug resistant and 2 susceptible) varieties to assess the effect of autoclaving at 105°C under 15 psi for 30 min on their protein quality, as measured by the levels of some antinutritional factors and performance of rats fed the different cowpea diets. Also, the relationships between antinutrients in the cowpeas and protein quality indicators were examined. Results showed that autoclaving completely eliminated trypsin inhibitor, hemagglutinin and HCN, whereas it reduced significantly (p<0.01) the levels of phytic and tannic acids in the cowpeas. In both raw and autoclaved forms, the insect susceptible cowpeas were better (P<0.05) utilized than their resistant counterparts, a condition which was attributable to lower levels of antinutrients in the susceptible varieties. In the raw cowpeas, trypsin inhibitor, hemagglutinin and HCN were significant variables affecting cowpea protein utilization, while in autoclaved samples, tannic and phytic acids were important though nonsignificant (P>0.05) factors. It was concluded that autoclaving at the above temperature and time improved the protein quality of the insect susceptible more than the insect resistant cowpea varieties.     

Compositional,functional and storage properties of flours from raw and heat processed African breadfruit (Treculia africana Decne) seeds

African breadfruit (Treculia africana Decne) seeds were either boiled or roasted and then milled into flour. Chemical composition, functional properties and storage characteristics of raw and treated flours and the effect of partial proteolysis on selected functional properties of the raw flour were determined. Raw flour contained 20.1% crude protein, 2.5% total ash and 13.7% fat. Heat processing significantly (p<0.05) improved in vitro protein digestibility, and water and fat absorption capacities but decreased bulk density, nitrogen solubility, emulsion and foaming properties, trypsin inhibitor, and phytic acid and polyphenol contents of the samples. Boiling proved more effective than roasting for improving protein digestibility, emulsion capacity and foam stability and reducing antinutritional factor levels. Partial proteolysis increased nitrogen solubility, bulk density and water and fat absorption capacities but decreased foam capacity at hydrolysis levels greater than 35%. Fatty acid and peroxide values of the samples increased during storage. Compared to raw samples, heat processed samples had significantly (p<0.05) lower and more acceptable peroxide values and free fatty acid contents and higher and more stable water (3.0 g/g sample) and fat (2.4 g/g sample) absorption capacities.     

Amino acid composition protein quality and water-soluble vitamin content of germinated cowpeas (Vigna unguiculata)

Amino acid composition, protein digestibility, calculated protein efficiency ratio (C-PER and DC-PER), chemical scores and water-soluble vitamin content of cowpea seeds germinated at 25°C or 30°C for 24h were determined. Also, the effect of processing steps (heated-air drying, decortication and cooking) on these parameters were examined. Germination had little effect on amino acid profile of cowpeas. In vitro protein digestibility was not improved significantly by germination nor by decortication but was improved by cooking. C-PER and DC-PER ranged from 1.95 to 2.21 and from 1.63 to 1.82, respectively. DC-PER compared well withreported rat PER of cowpea products and seemed more sensitive than C-PER. Based on whole egg values, chemical scores ranged from 37.7 to 45.8% (mean±SD; 42.2±2.4%). Germination increased the contents of niacin, thiamin and riboflavin significantly. Decortication resulted in up to 30% loss in niacin while thiamin content was reduced 41% by cooking.     

Cultivar and processing effects on the pasting characteristics,tannin content and protein quality and digestibility of cowpea (Vigna unguiculata)

Four popular West African local cultivars of cowpea (Vigna unguiculata), with distinctly different seed coat colors, were evaluated for their relative amylograph pasting characteristics, condensed tannin content, in vitro protein digestibility and Tetrahymena protein efficiency ratio (t-PER). The effects of roasting and dehulling on these properties were also determined. There were wide variations in the hot paste viscosity characteristics of the different cultivars studied. The raw cowpea flour samples exhibited maximum paste viscosities ranging between 260 Brabender Units (BU) for the Mottled cultivar and 460 BU for the cream-colored Blackeye cultivar. Cowpea cultivars with the greatest peak viscosities showed low stabilities to extended cooking. Roasting depressed paste viscosity properties of all the cowpea cultivars studied. Tannin concentrations were 0.3–6.9 and 7.2–116 mg CE/g flour from whole cowpea seeds and seed coats respectively, increasing with intensity of seed color. Although dehulling removed 98% of the tannin content of raw cowpeas, improvement in protein quality as a result of dehulling was observed for only the highly-pigmented Maroon-red variety. Roasting significantly improved digestibility and more than doubled the t-PER of all cowpea cultivars studied. Roasted cowpeas possess adequate nutritional and functional qualities as protein supplements in cereal-based weaning foods. However, it appears that dehulling is necessary to enhance the nutritional quality of the highly pigmented cultivars of cowpea.     

小麦淀粉的粒度分布、组分及糊化特性对氮硫肥的响应

为明确氮硫肥对小麦淀粉粒度分布及主要理化特性的影响,以强筋小麦品种西农9718和中筋品种陕农138为材料,采用不同氮硫肥水平进行处理,系统分析了小麦A、B淀粉的粒度分布、淀粉组成、膨胀势及糊化特性对氮硫肥的响应。结果表明,强筋和中筋小麦品种的淀粉粒度分布基本一致。A淀粉粒体积分布占总淀粉的74.95%～75.43%,但淀粉粒数量远少于B淀粉粒。A淀粉的直链淀粉、峰值黏度、低谷黏度、崩解值、最终黏度以及回生值高于B淀粉,而B淀粉有更高的支链淀粉、膨胀势和糊化温度。不同氮硫肥处理改变了小麦淀粉的粒度分布,进而影响淀粉的组成和糊化特性。在施氮(230kg.hm-2)条件下,强筋品种西农9718和中筋品种陕农138的A、B淀粉分别在硫肥施用量为46和56kg.hm-2时有较低的直链淀粉含量、较高的膨胀势及较好的糊化特性。陕农138淀粉的粒度分布、组成及糊化特性对氮硫肥的响应比西农9718更敏感。适当的氮、硫肥配施有利于改善小麦的淀粉品质。     

Use of two varieties of hard-to-cook beans (Phaseolus vulgaris) and cowpeas (Vigna unguiculata) in the processing of koki (a steamed legume product)

Koki is a nutritious cowpea-based food product usually processed by steam cooking whipped cowpea (Vigna unguiculata) paste mixed with spices and palm oil. A study was carried out to investigate the effect of the partial replacement of cowpeas (CP) with hard-to-cook (HTC) beans on the chemical, nutritional and sensory characteristics of koki. Towards this objective, two varieties of beans – Phaseolus vulgaris (red kidney beans – RKB and mottled brown beans – MBB), each with the HTC defect, were separately incorporated into cowpea paste in the following Bean:CP ratios 0:100, 20:80, 30:70, 40:60, 50:50, 60:40 and processed into koki. Incorporation of dry HTC beans into cowpeas in the making of koki affected the bulking properties of the uncooked paste, the nutrient composition, essential amino acid content, antinutritional factors, digestibility as well as the sensory attributes of cooked koki. Sensory tests showed that a highly acceptable, nutritious and digestible koki can be processed from cowpeas partially replaced with dry HTC bean paste up to levels of about 40–50% depending on the variety of dry bean used.     

不同糯小麦品种(系)品质及其烘烤制品研究

为推动糯小麦的品质改良及开发利用,以国内不同育种单位育成的多个糯小麦为试验材料,以普通强筋、中筋及弱筋小麦作为对照,分析其淀粉组分、糊化特性、面团流变学特性,并对其制作的酥条进行比较。结果表明,糯小麦的淀粉含量及直链淀粉含量显著低于普通小麦;在淀粉糊化特性上,糯小麦的低谷黏度、最终黏度、回生值显著低于普通小麦,峰值温度高于普通小麦;在粉质仪参数上,糯小麦的吸水率显著高于普通小麦,形成时间、稳定时间及粉质质量指数均显著低于师栾02-1,糯小麦弱化度较高,显著高于师栾02-1和扬麦158;糯小麦制作的酥条体积、酥性显著高于普通小麦,硬度显著低于普通小麦,气孔大且均匀,横截面积明显大于普通小麦。不同糯小麦品种(系)间比较,扬17G76、天糯158、扬14-282及扬糯麦1号在面团流变特性和制作酥条上表现较为优异,表明通过提高糯小麦筋力有助于改善糯小麦面团流变学特性及烘烤食品品质。本研究结果可为糯小麦育种及品质改良提供理论依据。     

不同木薯品种（系）块根淀粉特性研究

对79个木薯品种(系)块根淀粉的鲜薯含粉率、原淀粉水分、直链淀粉和支链淀粉含量、峰值粘度、糊化温度、透明度、恩氏粘度、淀粉粒直径和表面积等淀粉特性指标进行研究.结果表明,不同木薯品种(系)各淀粉特性指标存在很大的差异,不同指标间也有一定的相关性,利用主成分分析对各品种(系)各指标进行综合分析,认为E169、C766、E1424、E339、R72、E217、E344、E232、E316和桂热3号木薯淀粉的加工特性最好,更适合木薯淀粉的深加工.     

施氮量对糯小麦和非糯小麦籽粒淀粉组分与理化特性的影响

为探明氮肥对小麦籽粒淀粉组分和理化特性的影响,采用田间试验,分析了4个施氮量(0、100、200、300kg·hm~(-2))对糯小麦(农大糯50222)和非糯小麦(轮选987)籽粒淀粉组分与理化特性的影响。结果表明,随施氮量的增加,小麦籽粒淀粉含量降低,轮选987籽粒中B型淀粉粒的数目占比增加,而农大糯50222籽粒的B型淀粉粒数目占比呈减少趋势;增施氮肥能显著提高小麦籽粒淀粉的峰值黏度和谷值黏度。相同施氮量处理下,轮选987淀粉的被测糊化特征参数(除谷值黏度外)均大于农大糯50222。施氮量不同,2个品种籽粒淀粉X-衍射图谱中各峰的位置和相对强度明显不同。随施氮量的增加,轮选987淀粉的相对结晶度增大,而农大糯50222淀粉的相对结晶度减小。相关分析表明,小麦籽粒的直链淀粉含量和直支比与最终黏度、稀澥值、反弹值、糊化温度和峰值时间呈显著正相关,与谷值黏度和相对结晶度呈显著负相关;支链淀粉含量反之。小麦籽粒的B型淀粉粒数目占比与峰值黏度、稀澥值呈显著负相关。综上所述,施氮量可影响小麦籽粒的淀粉含量和粒度分布,进而改变其糊化特性和晶体特征。     

广西沿海地区豇豆小拱棚覆膜春季提早直播栽培技术

小拱棚覆膜春季提早直播栽培技术根据豇豆的生长对温度、光照、水份和养分的要求,在豇豆播种后,搭建小拱棚覆盖薄膜防寒保温保湿育苗,并配合选择适合生产外销嫩豆荚的良种,精细整地并施足基肥,适时播种,加强田间管理,搞好病虫害防治和适时采收等技术措施,提早一个季节播种,生产出优质豇豆外销北方市场,抢占市场先机,获得了较高的市场销售价格,经济和社会效益显著。     

早籼稻米RVA谱特性的品种间差异及其温度效应特征

采用粘度快速测定仪分析了10个不同食味类型早籼品种的淀粉粘滞（RVA谱）特性,并通过人工气候箱控温处理试验对早籼稻米淀粉粘滞特性与水稻灌浆结实期温度间的关系进行了分析。结果发现,食味较优的早籼水稻品种一般具有较大的崩解值和较小的消减值、回冷恢复值,而食味较差的早籼品种则相反,普遍有着较小的崩解值和较大的消减值、回冷恢复值,具有较明显的规律性;而不同食味类型早籼品种在最高粘度、热浆粘度、最终粘度等指标上差异规律则不明显;水稻灌浆结实期温度处理对早籼稻米淀粉粘滞特性的影响主要表现在淀粉糊化过程的回冷特性上,与高温处理相比,水稻在适温处理下灌浆,其稻米淀粉的最终粘滞度、消减值和回冷恢复值呈现出明显的上升趋势,而崩解值的变化则相对较为复杂。适温处理下稻米淀粉RVA谱特征的最终粘滞度、消减值和回冷恢复值等指标的变化,可能正是部分早籼品种“翻秋”种植后其蒸煮食味品质明显变好的一个重要理化指标。     

稻米中蛋白质对淀粉RVA特征谱的影响

通过分析蛋白酶或还原剂二巯基苏糖醇（DTT）分别去除稻米蛋白质或打破蛋白质二硫键后,稻米RVA（Rapid Visco Analyzer）特征谱形成和特征值的变化,研究蛋白质对淀粉RVA特征谱的影响,以及对米饭食味品质的作用。在淀粉糊化过程中,蛋白质使RVA特征谱的峰值黏度、冷胶黏度等值升高,改变RVA线性上升段的斜率。蛋白质可能通过二硫键结合形成的蛋白质网络本身和通过吸水减少淀粉水合的有效水量,协同提高糊化多相体系的浓度,增强分散相与黏稠相的互作。蛋白质影响米饭食味品质,可能通过改变米粒的吸水性而起作用。     

Nutritional quality of germinated cowpea flour (Vigna unguiculata) and its application in home prepared powdered weaning foods

Amino acid profiles, protein digestibility corrected aminoacid scores (PDCAAS), chemical scores, essential amino acid indexes, andcalculated biological values of control-cowpea flour (CCF), germinated cowpeaflour (GCF) prepared from cowpeas germinated at 25 ^°C for either24 h or 48 h and weaning foods prepared from cowpea flours weredetermined. Locally available rice, cowpea flour, banana-pumpkin slurry,and skim milk powder and sucrose in the ratio 35:35:15:15:5 were used to formulateweaning food containing not less than 15% protein. The ingredients werecooked into a slurry and oven-dried to produce flakes. The nutritional andsensory qualities of the weaning products were evaluated. Germination hadlittle effect on the amino acid profile of cowpeas. In vitro proteinquality and starch digestibility were improved in germinated cowpea flour. The PDCAAS of 24 h germinated cowpea flour (GCF) weaning food washigher (55.49%) than CCF-weaning food (46.74%). Vitamin A activityin 24 h GCF weaning food was higher than in CCF-weaning food. Invitro starch digestibilities of 24 h GCF and 48 h GCF-weaning foods werehigher than that of CCF weaning food. The 24 h GCF-weaning food which hada higher overall acceptability score by sensory panelist than 48 h GCFand CCF-weaning food is recommended for household consumption.     

氮肥对水稻胚乳淀粉品质、相关酶活性及基因表达量的影响

【目的】旨在为阐明灌浆成熟期氮素营养对水稻淀粉品质影响机理以及建立优质高产水稻栽培技术提供理论依据。【方法】选用4个籽粒直链淀粉含量差异显著的粳稻品种,通过盆栽试验研究氮素营养对稻米淀粉组分和蛋白质含量及稻米蛋白质水解对淀粉黏滞特性的影响,并分析氮素营养对灌浆过程中籽粒蔗糖合酶(SuSy)、蔗糖磷酸合酶(SPS)、蔗糖酸性转化酶(AI)活性及OsGBSSⅠ、OsISAⅠ、OsSBEⅠ、OsSBEⅡ基因转录表达量的影响。【结果】结果表明,籽粒支链淀粉含量对氮素营养很敏感,灌浆成熟期氮素营养能改变籽粒淀粉组分含量;施氮条件下,高直链淀粉含量品种蒸煮食味品质下降更加明显,去除稻米蛋白质可明显提高稻米黏滞特性,蛋白质对淀粉黏滞特性的影响很大;增加灌浆成熟期氮素营养能显著或极显著提高籽粒SuSy和AI活性,显著抑制籽粒SPS活性;灌浆成熟期氮素营养能改变灌浆不同时期籽粒OsGBSSⅠ、OsISAⅠ和OsSBEⅡ基因转录表达量,以致灌浆过程中这些基因的转录表达量变化动态发生改变,但OsSBEⅠ基因转录表达量不因氮素营养而发生改变;受氮素营养的影响,灌浆起始期籽粒OsGBSSⅠ基因表达量明显上调,而灌浆中后期明显下调;氮素营养明显抑制灌浆成熟期籽粒OsISAⅠ基因和灌浆中后期的OsSBEⅠ基因转录表达,显著提高灌浆前期和中期的籽粒OsSBEⅠ基因转录表达量;氮素营养能抑制灌浆起始期籽粒OsSBEⅡ基因的转录表达,而提高灌浆中后期的基因转录表达。【结论】灌浆成熟期氮素营养除了通过蛋白质含量对淀粉品质产生影响外,还通过调控淀粉合成相关的酶活性和基因表达量等生理环节对淀粉含量和精细结构起作用,最终改变稻米黏滞特性和食味品质。     

Starch Digestibility and Physicochemical and Cooking Properties of Irradiated Rice Grains

This study evaluated the starch digestibility, physicochemical properties and cooking characteristics of polished rice (varieties IRGA417 and IAC202) subjected to the doses of 0 (as the control), 1, 2 and 5 kGy of gamma radiation. The highest dose decreased the apparent amylose content, peak viscosity, water absorption and volume expansion. Irradiation increased the solid loss by 119% and 187% for IAC202 and IRGA417, respectively, when comparing the higher dose with the control. For IAC202, irradiation decreased the rapidly digestible starch and increased the slowly digestible starch (SDS) and resistant starch (RS). IRGA417 showed an elevation of SDS and a reduction in RS. And 1 kGy dose of gamma radiation generated the highest level of RS for both the two varieties and presented the smallest changes in other physicochemical and cooking properties.     

Physical properties of cryomilled rice starch

Cryomilling of rice starch was evaluated as a non-chemical way to modify starch structure and properties. Cryomilling in a liquid nitrogen bath (63–77.2 K) was done to Quest (10.80% amylose) and Pelde (20.75% amylose) rice starch at five different time frames (0, 15, 30, 45, and 60 min). The viscosity of the cryomilled rice starch decreased significantly (p < 0.05) with increasing milling duration, including peak viscosity, hot-paste viscosity, cold-paste viscosity, breakdown, and consistency. Increasing milling time significantly increased (p < 0.05) water solubility index and water absorption index. Infra-red spectroscopy and X-ray diffraction crystallography both showed that the crystallinity of the cryomilled starch decreased with increasing milling time. Differential scanning calorimetry (DSC) analyses showed that after 60 min cryomilling there was partial loss of crystallinity (86% for Quest and 91% for Pelde) of both cryomilled starches. The cryomilling process modified the rice starch by causing a loss of crystallinity, that reduced its pasting temperature and increased water absorption, and by fragmentation of starch (probably the amylopectin fraction) that reduced the viscosity and increased solubility.     

小麦铭贤169休眠解除期间种子结构与主要成分的变化

为探究小麦种子休眠解除期间的成分变化对发芽率的影响,了解种子休眠解除机制,以铭贤169为材料,在收获后不同储藏时间（间隔20 d）取样,通过显微设备观察了种子后熟期间的结构变化,测定了相关生理指标和成分,以探究铭贤169种子休眠性原因。结果表明,铭贤169种子休眠解除过程中,种皮细胞结构、组织结构、淀粉粒结构、蛋白基质等均发生变化,淀粉含量、粒径、糊化特性、热稳定性随贮藏时间延长变化显著。铭贤169的离体胚在花后25 d就具有发芽能力,但种子在花后35 d仍处于休眠。收获后熟期间,种胚活性、种子吸水率、含水量、淀粉含量、淀粉糊化谷值粘度和峰值时间、热稳定性逐步上升,与发芽率正相关。A型淀粉粒表面破损,淀粉粒与蛋白质结合紧密,种皮结构松散;淀粉粒径、淀粉酶活性、可溶性糖含量和沉降值减小;面筋和粗蛋白含量变化不大。推测铭贤169种子的休眠性与种子母体成分有关,休眠解除期间发芽率变化受种皮结构、淀粉的分解程度、淀粉粒与蛋白质的结合方式、可溶性糖含量、淀粉含量和性质以及淀粉酶活性等因素影响。