Soybean variety and storage effects on soymilk flavour and quality

Soymilk prepared from five soybean cultivars, grown in Ontario, were analysed for protein, oil, mineral composition, viscosity, colour, lipoxygenase (LOX) activities and flavour profile. Among the five soybean cultivars, the Vinton 81 variety contained the highest protein and the lowest fat. The yield of soymilk from all five cultivars was similar. Major differences were observed in viscosity and in the composition of both the soymilk and the okara. Higher protein and fat extractability was found in soymilk made from S08‐80 and Vinton 81 varieties. Their okara protein contents were also among the highest. Minimum extractability was observed with S03W4 cultivar. Soymilk made from S 03W4 and Vinton 81 cultivars had the whitest colour (lowest ΔE values). Viscosity values were the highest for S08‐80, FG1 and S20‐20 varieties. Headspace solid‐phase microextraction gas chromatography was used to analyse volatile compounds in soymilk. A total of fourteen volatiles were identified, among which aldehydes and their corresponding alcohols were the major compounds. Similar volatile compounds were identified in all the samples analysed but at different concentrations. The highest LOX activity was observed in the Vinton 81 and S20‐20 soybean cultivars, which had the highest total volatile and hexanal contents. A positive correlation (correlation coefficient = 0.82) between enzymatic activity and the total volatiles was observed. Vinton 81 cultivar was subjected to storage (at 18 °C and 50% relative humidity) for a period of 10 months. Soymilk was prepared at different times during storage. The results showed that the soymilk colour, LOX and total volatiles were significantly (P < 0.05) affected by the storage of the soybeans over time.     

Characterization and Study of Transgenic Cultivars by Capillary and Microchip Electrophoresis

Advances in biotechnology have increased the demand for suitable analytical techniques for the analysis of genetically modified organisms. Study of the substantial equivalence, discrimination between transgenic and non-transgenic cultivars, study of the unintended effects caused by a genetic modification or their response to diverse situations or stress conditions (e.g., environmental, climatic, infections) are some of the concerns that need to be addressed. Capillary electrophoresis (CE) is emerging as an alternative to conventional techniques for the study and characterization of genetically modified organisms. This article reviews the most recent applications of CE for the analysis and characterization of transgenic cultivars in the last five years. Different strategies have been described depending on the level analyzed (DNA, proteins or metabolites). Capillary gel electrophoresis (CGE) has shown to be particularly useful for the analysis of DNA fragments amplified by PCR. Metabolites and proteins have been mainly separated using capillary zone electrophoresis (CZE) using UV and MS detection. Electrophoretic chips have also proven their ability in the analysis of transgenic cultivars and a section describing the new applications is also included.     

北方麦区120个小麦品种抗秆锈病基因的推导

利用含已知Sr5～38、SrGT和SrWld基因的42个单基因系和19个不同毒性的秆锈菌系，对北方麦区的120个生产品种和后备品系进行了抗秆锈病的基因推导．研究结果表明：黄淮冬麦区和北方冬麦区抗病品种（系）含有的抗秆锈病基因相似，绝大多数品种（系）主要含有Sr5、Sr31，少量品种含有Sr11、21、29等抗病基因；东北春麦区的小麦抗病品种（系）主要含有Sr5、6、8a、9b、9e、11、21、27、30、31、34、36等多基因组合。     

Volatile compounds characterising Tunisian virgin olive oils: the influence of cultivar

In this work, the volatile profiles of four Tunisian virgin olive oils were established by headspace‐solid phase microextraction and gas chromatography, using flame ionisation and mass spectrometer detectors. More than eighty compounds were isolated and characterised, representing 97–99% of the total GC area. The main volatile compounds present in the oil samples were determined quantitatively, the major constituents were often aldehydes, particularly (E)‐2‐hexenal (48–90%). Significant differences in the content of volatile constituents were observed. These quantitative differences were used to distinguish between virgin olive oils from different varieties.     

Effects of Boiling and Storage on Dietary Fibre and Digestible Carbohydrates in Various Cultivars of Carrots

The influence of boiling and storage on dietary fibre and digestible carbohydrates was investigated in eight different carrot cultivars. The content of total dietary fibre was in the range 252–291 g kg^-1 DW and was generally at the higher end for the early cultivars and at the lower end for the late ones. During storage, there was a decrease in the soluble fibre content in all cultivars and generally an increase in insoluble fibre. Following boiling, the loss of dietary fibre varied considerably between cultivars. After storage, the loss could be correlated to the average root weight of the carrot cultivars. The total content of glucose, fructose and sucrose was rather similar in the various cultivars, whereas their individual distribution differed. Storage had generally minor influence on the sugar content, except in the cultivars Amarant and Bull. On boiling, the loss was solely dependent on the initial sugar concentration. After storage the loss increased, which could be related to the lower dry matter content. The choice of cultivar and storage time is important in interpreting analytical data from carrots and is probably of similar significance in other vegetables when studying effects of heat treatment. © 1997 SCI.     

Natural antioxidants in the unsaponifiable fraction of virgin olive oils from different cultivars

An investigation on carotene, α-tocopherol and squalene contents of olives from six different cultivars and 15 virgin olive oils produced in Molise region in 1995 was carried out. Olives were harvested at different stages of ripeness and oil was extracted in industrial plants by pressure or centrifugation systems. The concentration of carotenes, α-tocopherol and squalene have been correlated, both in fruit and oil samples, with the olive ripeness index. In particular a significant linear correlation (R²=0·95) has been found between olive ripeness index and olive carotene content. In order to evaluate the stability of the extracted oil, a 6 month storage test at room temperature in the dark has been carried out. In addition to the nutritional relevance of β-carotene and α-tocopherol, the compounds studied are also characterised by antioxidant activities. Within the same cultivar, tocopherol and squalene stability was inversely related to the degree of ripeness. In general, storage losses ranged, probably due to different antioxidant mechanisms, from 0 to 10% for carotene, from 14 to 32% for tocopherol and from 26 to 47% for squalene. © 1998 SCI.     

Effect of refining of crude rice bran oil on the retention of oryzanol in the refined oil

The effect of different processing steps of refining on retention or the availability of oryzanol in refined oil and the oryzanol composition of Indian paddy cultivars and commercial products of the rice bran oil (RBO) industry were investigated. Degumming and dewaxing of crude RBO removed only 1.1 and 5.9% of oryzanol while the alkali treatment removed 93.0 to 94.6% of oryzanol from the original crude oil. Irrespective of the strength of alkali (12 to 20° Be studied), retention of oryzanol in the refined RBO was only 5.4–17.2% for crude oil, 5.9–15.0% for degummed oil, and 7.0 to 9.7% for degummed and dewaxed oil. The oryzanol content of oil extracted from the bran of 18 Indian paddy cultivars ranged from 1.63 to 2.72%, which is the first report of its kind in the literature on oryzanol content. The oryzanol content ranged from 1.1 to 1.74% for physically refined RBO while for alkali-refined oil it was 0.19–0.20%. The oil subjected to physical refining (commercial sample) retained the original amount of oryzanol after refining (1.60 and 1.74%), whereas the chemically refined oil showed a considerably lower amount (0.19%). Thus, the oryzanol, which is lost during the chemical refining process, has been carried into the soapstock. The content of oryzanol of the commercial RBO, soapstock, acid oil, and deodorizer distillate were in the range: 1.7–2.1, 6.3–6.9, 3.3–7.4, and 0.79%, respectively. These results showed that the processing steps—viz., degumming (1.1%), dewaxing (5.9%), physical refining (0%), bleaching and deodorization of the oil—did not affect the content of oryzanol appreciably, while 83–95% of it was lost during alkali refining. The oryzanol composition of crude oil and soapstock as determined by high-performance liquid chromatography indicated 24-methylene cycloartanyl ferulate (30–38%) and campesteryl ferulate (24.4–26.9%) as the major ferulates. The results presented here are probably the first systematic report on oryzanol availability in differently processed RBO, soapstocks, acid oils, and for oils of Indian paddy cultivars.     

The influence of phenolic extracts obtained from the olive plant (cvs. Picual and Kronakii), on the stability of sunflower oil

Summary The phenolic compounds of olive cultivars (Picual and Kronakii) were extracted. The total phenolic content of the extracts was estimated and their ability to reduce the oxidation of sunflower oil was tested at 100 °C by using a Rancimat^®. The fruits, leaves and pomaces were extracted separately with ethanol. Portions of the fruits were crushed to produce an oil/aqueous mixture, which was separated and the two fractions further processed. The oil fraction was extracted with 60% aqueous methanol and was separated further, by the method of Dabrowski & Sosulski (1984 ), into three major fractions. These contained mainly free phenols, soluble phenolic esters or bound phenolic acids, respectively. The phenolic concentrations were measured in all the fractions and were in accordance with expected amounts. When tested at 100, 200 or 400 ppm for their ability to stabilize sunflower oil the results showed that the vast majority of the anti‐oxidant activity found in the ‘total phenols’ fraction was because of a ‘free phenolic’ group. The free phenolics, at a 400‐ppm level, exhibited remarkable anti‐oxidant activity and were superior to that of butylated hydroxy toluene (BHT) in retarding sunflower oil oxidative rancidity. The mode of action is discussed.