Baking quality versus some biological activities of proteins extracted from the grain of wheat varieties harvested in 1986

Grain of six winter and spring wheat varieties differing in baking quality were included in the study. A number of technological analyses were performed. Albumins, globulins and gliadins were washed out. Location of inhibitory activities of alpha-amylases in extracted proteins against enzymes of various origin were tested and compared to baking quality of the wheat grain. Also, the location of endogenous amylase activity in extractable proteins was compared to baking quality of the studied varieties. A certain correlation between the incidence of higher inhibition activity against alpha-amylase of Sitophilus granarius L. and good baking quality has been found. However, location of endogenous alpha-amylases in grain seems to be a better criterion classifying varieties according to their baking quality. So-called baking varieties have higher and only activity of endogenous alpha-amylases located in albumin and gliadin fractions, whereas in poorest, “non-baking” varieties this activity is also located in the globulin fraction.     

The varietal identification of single seeds of wheat by sodium dodecyl-sulphate polyacrylamide gel electrophoresis of gliadin

Sodium dodecyl-sulphate polyacrylamide gel electrophoresis of gliadin is used to distinguish between wheat varieties which cannot be differentiated by starch gel electrophoresis. The technique identifies differences in high molecular weight gliadin polypeptides between the bread wheat varieties Sappo and Sicco, Flanders and Chalk, Cappelle Desprez and West Desprez and the three Durum varieties Durtal, Rikita and Lakota.     

冬小麦抗冻蛋白制备及其在汤圆中的应用研究

研究了冬小麦麸皮抗冻蛋白的制备方法及其在速冻汤圆中的应用。研究确定冬小麦麸皮抗冻蛋白的提取工艺为:pH8.0,提取时间3h,液料比5:1,该条件下小麦麸皮水溶性蛋白质提取率达到38%,其中含抗冻蛋白1.6%。抗冻蛋白粗品在汤圆中的应用实验结果显示,2.5%的蛋白添加量对汤圆的品质有明显的改善效果。      

The influence of γ-irradiation on some biological activities and electrophoresis patterns of wheat grain albumin fraction

Water-soluble proteins were extracted from irradiated wheat grain for the purpose of assaying biological activities, reducing sugars content and SDS–PAGE electrophoresis. The differences between samples after γ-irradiation were tested by analysis of variance at the level of significance (P ? 0.05). Ionising radiation (0.05–10 kGy) caused an increase in the activity of endogenous amylases, statistically significant at doses of 5 and 10 kGy (P ? 0.05), which was well correlated with the highest extractable protein content. γ-Irradiation of wheat grain at a dose of 0.05 kGy caused an increase of inhibition activity against Sitophilus granarius L. α-Amylase, whereas there was a decrease at 10 kGy (P ? 0.05). On the other hand, grain irradiated by 0.5 and 1 kGy doses showed a significant increase in inhibition activity against α-amylase of Tribolium confusum Duv. (P ? 0.05) while at the remaining doses the inhibition activity was on the same level as the control grain. Decrease of Ephesitia kuehniella Zell. α-amylase was observed only at 5 kGy radiation dose (P ? 0.05). At the remaining doses this activity was comparable to non-irradiated grain.     

油茶籽多酚提取物生物活性的研究

山茶籽油是我国特色食用油,具有多种活性,多酚是其主要功能成分之一。为探究油茶籽多酚的活性特点,研究比较了15个油茶籽多酚样品和5种非油茶植物多酚(肉桂多酚、苹果多酚、葡萄皮多酚、紫锥菊多酚、石榴皮多酚)抑制脂氧合酶(lipoxidase, LOX)、环氧合酶-2(cyclooxygenase 2,COX-2)、 α-葡萄糖苷酶、α-淀粉酶和胰脂肪酶活性,羟自由基清除率、超氧阴离子清除率,抗脂质氧化活性,并通过“蓝精灵”实验评估了多酚对果蝇肠炎的抑制活性。结果表明：油茶籽多酚提取物对几种酶均有抑制作用,油茶籽多酚提取物对果蝇肠炎和LOX活性的抑制作用显著高于非油茶籽多酚提取物;相关性分析结果显示,多酚抗LOX活性和抗果蝇肠炎活性之间呈极显著正相关(r=0.725,P<0.01)。油茶籽多酚是α-葡萄糖苷酶选择性抑制剂,其抗炎效果强于非油茶籽多酚,抗氧化、抑制LOX活性可能是油茶籽多酚抗肠炎机制之一。     

Properties of some citrus seeds. Part 2. Functional properties of seed flours

Water and fat absorption, gelation, protein solubility, emulsification and foam capacities of flours from citron, orange and mandarin seeds were determined. The protein solubility of the flours was increased as sodium chloride concentration increased up to 0.8 M for citron, mandarin and mixture seed flours and 1 M for orange seed flour, then decreased at higher concentrations. The minimum solubility was sharp for mandarin and orange seed flours, while, it was broader for mixture and citron seed flours. The least concentration for forming gel was 6%, 6.5% and 7% for mandarin, orange and both citron and mixture seed samples, respectively. The flours of orange and mandarin seeds were the highest and lowest in water absorption capacity. Also, the highest value of fat absorption capacity was noticed for citron and lastly for mandarin on flour basis. The emulsification and foam capacity-pH patterns were similar to protein solubility-pH profiles for all citrus seed flours. Foam capacity of mandarin and mixture seed flour were lower than that of citron and orange seed flours. The emulsification and foam capacities patterns in sodium chloride solution showed an increase up to 0.6 M and then decreased in all citrus seed flours. Foam stability of citrus seed flours was increased with sodium chloride concentration up to about 0.6 M and then decreased. The foam stability of all citrus seed flours at pH 4.5 was very poor but at pH 2, it was comparable to that at pH 8.     

Functional properties of flours prepared from three Chinese indigenous legume seeds

The functional properties of Phaseolus angularis, Phaseolus calcaratus and Dolichos lablab flours were investigated and compared with those of soybean flour. The minimum nitrogen solubilities of P. angularis and P. calcaratus flours were at pH 5 while that of D. lablab flour was at pH 4. Compared with soybean flour, P. angularis, P calcaratus and D. lablab flours exhibited lower foam capacities, water- and oil-holding capacities, but higher gelation capacities. The emulsifying activities and emulsion stabilities of all legume flours tested were pH-dependent with minimum values at pH 4. Their emulsion stabilities were greater than 80.2% from pH 2 to 10, except at pH 4. Foam capacities and stabilities were also pH-dependent, highest foam stabilities being at pH 4.     

Chemical composition and starch digestibility in flours from Polish processed legume seeds

The study was undertaken to determine the effect of various treatments, i.e. cooking after soaking, freezing after cooking and storage at a low temperature (-18°C, 21days), and autoclaving, of Polish cultivars of bean, pea and lentil seeds on the chemical composition and starch digestibility of the resultant flours. The cooking of seeds caused a significant decrease in contents of ash (by 11-48%), polyphenols (by 10-70%) and protein (to 19%) in flours made of bean. In addition, analyses demonstrated significantly decreased contents of resistant starch, RS (by 61-71%) and slowly digestible starch, SDS (by 56-84%). Storage of frozen seeds resulted in insignificant changes in the chemical composition, and in increased contents of both RS and SDS. The flours produced upon the autoclaving process were characterized by similar changes in the contents of ash and protein as in cooked seeds, yet losses of polyphenols were lower and, simultaneously, contents of RS and SDS were higher. All the analyzed flours were shown to be characterized by a reduced content of amylose in starch, which might have affected its digestibility. This was indicated by a strict negative correlation reported between the value of the starch digestion index (SDRI) and amylose content of starch (r=0.84, p>0.05).     

白果分离蛋白、清蛋白和球蛋白功能特性的热稳定性

对白果分离蛋白(GPI)、白果球蛋白(GGP)和白果清蛋白(GAP)的功能特性在不同温度处理下的变化进行了研究。结果表明:不同温度对3种白果蛋白功能特性的影响趋势基本一致,在25⁵5℃处理后,3种白果蛋白的溶解性、吸水性、起泡能力和泡沫稳定性均得到显著增加,在55℃达到最大,温度再升高则产生不利的影响;吸油性则在5555℃处理后,3种白果蛋白的溶解性、吸水性、起泡能力和泡沫稳定性均得到显著增加,在55℃达到最大,温度再升高则产生不利的影响;吸油性则在55⁷5℃内呈快速增长,超过75℃,吸油能力反而下降;就乳化容量而言,GAP在55℃、GPI和GGP在65℃升至最高,再升高温度,蛋白质乳化容量下降;加热处理对白果蛋白质乳化稳定性的影响较大,随着温度的升高乳化稳定性均下降。GPI、GGP和GAP 3种蛋白质的变性温度分别为86.17、88.57℃和79.23℃,白果蛋白在高温功能特性下降可能与蛋白质变性密切相关。通过适度加热蛋白质溶液(5575℃内呈快速增长,超过75℃,吸油能力反而下降;就乳化容量而言,GAP在55℃、GPI和GGP在65℃升至最高,再升高温度,蛋白质乳化容量下降;加热处理对白果蛋白质乳化稳定性的影响较大,随着温度的升高乳化稳定性均下降。GPI、GGP和GAP 3种蛋白质的变性温度分别为86.17、88.57℃和79.23℃,白果蛋白在高温功能特性下降可能与蛋白质变性密切相关。通过适度加热蛋白质溶液(55⁷5℃),可使白果蛋白质的功能特性得到显著的改善。     

The action of pepsin on the reserve proteins of some leguminous seeds

The action of pepsin on the 11-S and 7-S proteins of vetch, 11-S protein of soybean and 7-S protein of Phaseolus vulgaris was investigated. The first three proteins are hydrolyzed almost completely, the rate of hydrolysis being close to that of hemoglobin, while the hydrolysis of Ph. vulgaris 7-S protein stops after the cleavage of only 2,4% of peptide bonds. The nonhydrolyzable high molecular weight core makes up to 87% of the initial protein and differs from the latter in its electrophoretic mobility and sedimentation coefficient. The action of pepsin does not increase the digestibility of Ph. vulgaris 7-S protein by trypsin. After the consecutive action of these enzymes about two thirds of the protein remain unhydrolyzed. The digestion of Ph. vulgaris 7-S protein by pepsin is completed only after its denaturation by heat treatment or by the action of 6 M guanidine hydrochloride.     

Occurrence of Penicillium verrucosum in retail wheat flours from the Spanish market

In Spain, low ochratoxin A (OTA) levels have been detected in wheat and different wheat products but no information has been published about the fungi involved in this OTA contamination. Some species of the genera Penicillium and Aspergillus are known to form OTA but few of them are known to contaminate foods with this mycotoxin. Penicillium verrucosum, an important OTA producer typical of temperate and cold climates, is much more frequently found on cereals in countries where they occasionally have OTA problems as in North European countries compared with South Europe, where levels of OTA generally seem to be lower or is not detected. The aim of this study was to determine, identify and characterize the occurrence of potential OTA-producing Aspergillus spp. and Penicillium spp. from retail wheat flours purchased in the Spanish market and used for human consumption. A total of 105 Aspergillus isolates were analyzed in order to know whether they are able to produce OTA and/or citrinin (CIT). None of these isolates were able to produce these mycotoxins. However, 17 suspected P. verrucosum isolates were recovered and confirmed by RAPD analyses. Eleven isolates were OTA producers and 14 isolates produced CIT. Our results confirm the potential risk of OTA and CIT production in wheat flours if stored improperly and the occurrence of P. verrucosum in South European countries. This was the only species able to produce these mycotoxins.     

花椒籽不同溶剂提取物的活性成分及抗氧化性比较

为明确不同溶剂对花椒籽活性物质及抗氧化活性的影响,给花椒籽的综合利用提供参考.以"大红袍"花椒籽为材料,比较不同溶剂提取(蒸馏水,30％、50％、70％的乙醇,30％、50％、70％的甲醇)对花椒籽中总多酚、总黄酮的含量及DPPH自由基清除率和铁还原能力(FRAP)的影响.结果表明,用90％乙醇提取的花椒籽总多酚含量最...     

The action of pepsin on the reserve proteins of some leguminous seeds.

The action of pepsin on the 11-S and 7-S proteins of vetch, 11-S protein of soybean and 7-S protein of Phaseolus vulgaris was investigated. The first three proteins are hydrolyzed almost completely, the rate of hydrolysis being close to that of hemoglobin, while the hydrolysis of Ph. vulgaris 7-S protein stops after the cleavage of only 2,4% of peptide bonds. The nonhydrolyzable high molecular weight core makes up to 87% of the initial protein and differs from the latter in its electrophoretic mobility and sedimentation coefficient. The action of pepsin does not increase the digestibility of Ph. vulgaris 7-S protein by trypsin. After the consecutive action of these enzymes about two thirds of the protein remain unhydrolyzed. The digestion of Ph. vulgaris 7-S protein by pepsin is completed only after its denaturation by heat treatment or by the action of 6 M guanidine hydrochloride.     

Total cyanide levels in bread made from wheat/cassava composite flours

Cyanide levels were determined in cassava flours and bread. It was found that incubation media had no effect on cyanide determination. For all the cyanide to be released, incubation was carried out with linamarase extract for 14 h, followed by prolonged aeration of the media. Cassava flour with low initial levels of HCN gave cyanide-free bread, whereas there was a retention of 8% of the original HCN in loaves obtained from cassava flours with initial high levels of HCN.     

大豆几丁质酶应用的研究

研究了大豆种子几丁质酶对壳聚糖的降解作用,采用测定壳聚糖溶液黏度降低和还原糖增加的方法。结果表明,大豆种子经甲壳低聚糖诱导后发芽的提取物作用于DD值为71.1%的壳聚糖15min,可使其乙酸盐溶液的VDP值达60%以上。初步纯化的大豆几丁质酶可降解壳聚糖释放还原糖,且较适合降解DD值低的壳聚糖,其作用于DD值71.1%的壳聚糖37.5h可得到平均聚合度为4￣5的水溶性甲壳低聚糖,得率为40%左右。大豆种子几丁质酶对壳聚糖有降解作用。