不同干燥方法对西兰花中萝卜硫素含量影响

采用阴干、50℃~90℃烘干及晒干三种常用干燥方式干燥西兰花的花、茎、叶,采用HPLC测定萝卜硫素含量。西兰花不同部位中萝卜硫素含量是种子>花>茎>叶;而不同干燥方法中烘干最好,阴干最差,5种烘干温度中以90℃烘干时萝卜硫素含量最高。西兰花不同部位中种子萝卜硫素含量最高,有10.48 mg/g;而干燥方式采用90℃烘干最佳。     

浓香型白酒风味轮的建立及其对感官评价的研究

通过对国外啤酒、葡萄酒、威士忌、白兰地等风味轮建立方法的学习,结合中国白酒的特色及国内对白酒风味成分的鉴定成果,构建浓香型白酒风味轮术语体系。并提供了其中50个感官描述语参比样的配制方法,定义了19个风味描述语,统一了白酒感官描述标准。同时利用多元统计技术对浓香型白酒的感官评价进行了研究。     

西兰花叶加工保健茶工艺研究

ZHAO Yuan-shou;DU Xi-mei;SU Xiao-hong;GAO Guo-qiang(Lanzhou Industrial Research Institute,Lanzhou 730050,China)     

Pressure-Temperature Degradation of Green Color in Broccoli Juice

Broccoli juice greenness was marginally affected by pressure at low temperatures (30-40°C). At 800 MPa and slightly higher temperatures (50-60°C), first-order degradation of green color was observed. The greenness loss was suggested to be due to chlorophyll-pheophytin conversion with no further pheophytin degradation. Pheophytin degraded further when higher temperatures (≥70°C) were combined with elevated (or atmospheric) pressures (0.1–850 MPa). At these conditions greenness loss could be modeled by two consecutive first-order degradation steps. Temperature dependency of the rate constants for both degradation steps could be described by the Arrhenius equation with activation energies increasing with pressure. However, their pressure dependency could not satisfactorily be described by the Eyring equation.     

Effect of Temperature and Light Exposure on the Detection of Total Intact Glucosinolate Content by LC-ESI-MS in Broccoli Leaves

Total intact glucosinolate content in broccoli leaf extracts (Ramoso calabrese cultivar) has been determined by liquid chromatography coupled to tandem mass spectrometry with the aim of detecting potential differences in this value due to the effects of the drying temperature or the working and storage conditions (temperature and light exposure). Those broccoli leaf extracts were obtained with two different sample treatments based on heating the sample (microwave or oven), and using boiling water as extraction solvent. Significant differences were observed in the total intact glucosinolate content depending on the drying temperature and light exposure under typical working conditions. Meanwhile, those differences were less remarkable when the extracts were stored at low temperature and protected from light exposure.     

Optimal Controlled Atmosphere Conditions for Storage of Broccoli Florets

Minimally processing broccoli heads into florets increased the rate of respiration throughout storage at 4°C in air, in response to wounding stress. Ethylene production was also stimulated after 10 days. At-mospheres for optimal preservation of the florets were evaluated using continuous streams of the following defined atmospheres (%CO₂/%O₂): O/20 (air control), 6/1, 6/2, 6/3, and 3/2, 6/2, 9/2. The atmosphere consisting of 6% CO₂+ 2% O₂ resulted in extended storage of broc-coli florets from 5 wk in air to 7 wk. This was demonstrated by delayed yellowing, prolonged chlorophyll retention, reduced development of mold and offensive odors (by sensory observation), and better water retention. These beneficial effects were especially noticeable when the florets were returned from CA at 4°C to air at 20°C.     

Glucosinolate and folate content in sprouted broccoli seeds

HPLC analysis of broccoli seeds and laboratory-grown broccoli sprouts revealed that three aliphatic glucosinolates (glucoraphanin, glucoiberin and glucoerucin) and a group of indol-glucosinolates including 4-hydroxy-glucobrassicin are preformed in the seeds. In the early stage of sprouting a reduction (approx. 20%) of the aliphatic glucosinolates was measured. During further growing, until day 8, and subsequent cold storage up to the 12th day the amounts of the aliphatic glucosinolates levelled off. While 4-hydroxy-glucobrassicin declined continuously, three minor indole-derivatives increased steadily, but remained at a comparatively low level. Besides glucosinolates, folates were quantified in broccoli sprouts by stable isotope dilution assays (SIDAs). During germination, the contents of total folates increased to 72 μg/100 g fresh mass and 546 μg/100 g dry mass on the 4th day, which was equivalent, respectively, to a 3-fold and a 24-fold increase in the seed’s content. Thereafter, total folates decreased again to 13 μg/100 g fresh mass until the 8th day of germination and remained at this low level. The folate pattern measured by SIDA revealed 5-methyltetrahydrofolate as the predominant vitamer at each stage.     

Daily Variation in Glucosinolate Concentrations in the Leaves and Roots of Cabbage Seedlings in Two Constant Temperature Regimes

Limited information is available on the glucosinolate variation within the Brassica plant and the relationship between the pattern and concentration of glucosinolates in the aerial parts and the roots has received little attention. Early studies carried out under field conditions have shown that glucosinolate levels may vary considerably throughout a 24 h period. The purpose of the present study was to show whether, under controlled conditions, temperature was a factor in glucosinolate variation and to determine whether such variation might be due to translocation of glucosinolates between the aerial parts of the plant and its roots. Cabbage seedlings were maintained at 20 and 30°C over 2 days and leaves and roots sampled at 02:00 h, 06:00 h, 10:00 h, 14:00 h, 18:00 h and 22:00 h. The glucosinolates 2-propenyl- and 3-methylsulphinylpropyl- with an average of 261 and 167 μmol 100 g^-1 DW, respectively, were the two main glucosinolates in the aerial part of the plant whilst in the roots 1-methoxyindol-3-ylmethyl-, 2-phenylethyl- and 3-methylsulphinylpropyl, with 495, 495 and 385 μmol 100 g^-1 DW respectively, showed the highest average concentrations. Total and individual glucosinolates in the roots and in the aerial part of the plant showed the highest concentrations in the dark cycle, at 02:00 h and 22:00 h, respectively, whilst the lowest levels were during the light cycle, mainly at 18:00 h. The results suggest that temperature was not a major factor in the short-term variation in glucosinolate levels. Although there was a very high significant difference between the total glucosinolate levels in the aerial part of the plant (581 μmol 100 g^-1 DW) and roots (2124 μmol 100 g^-1 DW), the results of the present study do not support the concept of translocation between aerial part and roots, suggesting that other factors may be involved. © 1997 SCI.     

采后青花菜花球抗氧化水平变化与衰老的关系

为研究采后青花菜花球抗氧化水平变化与衰老的关系,将采后青花菜花球贮藏于20℃条件下,连续4 d测定了花蕾衰老生理指标(叶绿素、蛋白质、丙二醛(MDA)含量)及抗氧化水平指标(抗坏血酸(AsA)和β-胡萝卜素(β-Car)含量、超氧化物岐化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)和抗坏血酸过氧化氢酶(APX)活性)。结果表明:贮藏过程中,叶绿素和蛋白质含量逐渐减少,MDA含量逐渐增多;AsA和β-Car含量逐渐减少,SOD、CAT和POD活性逐渐升高,APX活性逐渐降低;这些抗氧化水平指标与衰老生理指标的线性相关性均在1%水平显著。说明采后青花菜花球的抗氧化水平变化与衰老密切相关。     

冰点调节剂对西兰花冰点的控制研究

本文研究不同冰点调节剂对西兰花冰点的影响。实验选取葡萄糖、维生素C、氯化钙和山梨醇四种冰点调节剂,利用单因素比较实验法,系统研究了冰点调节剂种类及其使用条件对西兰花冰点的影响。结果表明,氯化钙是较好的冰点调节剂;3％氯化钙浸泡30rain对西兰花的冰点调节效果较好,使西兰花冰点从-0．8℃降到．1℃。     

The Glucosinolate Content of Some Fodder Brassicas

The glucosinolate contents of six kales and five cabbages (Brassica oleracea L.), four stubble turnips and six turnips (B. campestris L.), and six swedes and six fodder rapes (B. napus L.) were determined. As fodder brassica breeders wish to reduce the goitrogenicity of these crops, the concentrations of 2-hydroxybut-3-enylglucosinolate (5-vinyloxazolidine-2-thione is the goitrogenic hydrolysis product) and 3-indolylmethylglucosinolate (the thiocyanate ion is the goitrogenic hydrolysis product) were of particular interest. High concentrations (mmol kg^?1 dry matter) of 2-hydroxybut-3-enylglucosinolate were found in stubble turnip leaf (8.12) and bulb (9.20), turnip bulb (9.97), swede bulb (5.66), and rape leaf (8.99) and stem (21.81) but not in kale or cabbage. In contrast, the concentration of 3-indolylmethylglucosinolate was relatively high in cabbage head (6.39) and kale leaf (3.25) but not in the other crops.     

西兰花贮期黑斑病病原菌鉴定及防治技术研究

西兰花贮期主要病害是黑斑病,经病原菌鉴定,属芸苔生链格孢菌。4℃的低温只能抑制而不能终止该菌的生长,而35℃可有效抑制该菌的生长。pH在5~9的范围内菌落生长良好,pH低于3和高于11时该菌几乎完全受到抑制。臭氧和减压均能抑制该病原菌的生长,浓度为300 mg/m3的臭氧杀菌效果显著,浓度再增高,杀菌效果与300 mg/m3差异不显著,在101~20 kPa的压力范围内,压力越低,抑菌效果越好,以压力40 kPa较为理想。     

温度对西兰花抗氧化活性及其品质指标影响

研究0、10和20℃下,西兰花抗氧化活性及相关品质指标的变化规律,为西兰花采后不同温度条件下功能营养变化规律及适宜温度条件的确定提供参考。试验结果表明不同温度西兰花的黄化时间显著不同。10℃和20℃条件下,西兰花抗氧化活性、总酚含量、可溶性固形物含量等指标呈先升高后下降的趋势。与10℃和20℃相比,0℃能有效延长西兰花中VC、类黄酮、叶绿素、类胡萝卜素含量的保持时间,贮藏28 d时西兰花品质良好。采后短期贮藏有利于西兰花功能营养的提高。整个贮藏过程中西兰花的抗氧化活性与总酚含量相关性最大,其次是类黄酮,与VC和类胡萝卜素含量的相关性不大。     

Rapeseed Meals,Methimazole, Thiocyanate and Iodine Affect Growth and Thyroid. Investigations into Glucosinolate Tolerance in the Pig

In two factorial experiments with a total of 81 growing pigs, the effects of antithyroid compounds and rapeseed meal (RSM) diets differing in glucosino-late content were tested without or with supplementary iodine. In Experiment 1, a 4×3 factorial arrangement was used to investigate the effects of antithyroid compound inclusion and supplementary iodine. Pigs received a grain–soya bean meal diet (control) or this diet with 250 mg kg^-1 methimazole (MMI), 1000 mg kg^-1 thiocyanate (SCN^- as KSCN) or 80 g kg^-1 high glucosinolate RSM (9·5 mmol glucosinolates kg^-1), each diet supplemented without or with iodine; 0, 125 μg kg^-1 (requirement) or 500 μg kg^-1. In Experiment 2, a 5×3 factorial arrangement was used to study the effects of dietary glucosinolate content and iodine supplementation. Pigs received a grain–soya bean meal diet or four diets with 160 g kg^-1 RSM differing in glucosinolate content (0·6, 2·4, 6 or 19 mmol kg^-1 diet), each diet supplemented with iodine: 62·5 μg kg^-1, 125 μg kg^-1 (requirement) or 250 μg kg^-1. Irrespective of the iodine dosage, MMI suppressed production of thyroxine and resulted in goitre, myxoedema and cretinism. SCN^- induced clinical hypothyroidism when there was no supple-mental iodine. Despite high iodine supplementation, glucosinolate load (19 mmol kg^-1 diet) decreased growth, feed intake, iodine store of the thyroid and serum concentration of thyroid hormone and resulted in goitre formation. In the case of diets with ⩽6 mmol glucosinolates kg^-1, iodine prevented antithyroid effects. However, more iodine was required by these pigs than by control animals to a high T₄ serum concentration. The lowest glucosinolate level tested (0·6 mmol kg^-1 diet) yielded the same thyroid hormone status and thyroid weight as the control, however, the iodine content of thyroid gland was decreased. In conclusion, iodine administration prevents the effects of a low glucosinolate intake only, by overcoming the depressed thyroxine released of the thyroid, resulting in regression of goitre. © 1997 SCI.