Glycoalkaloid Concentration in Potato Tubers Related to Storage and Consumer Offering

Steroidal glycoalkaloids (SGA) are unwanted potato constituents for consumers because they are highly toxic and therefore have to be controlled in the food chain. Three experiments were carried out focusing on storage aspects and on exposure to artificial light at the point of sale. The experiments showed that an elevated temperature (10 °C) during long-term storage without sprouting inhibitors led to an increase in SGA contents (up to 518 mg SGA kg⁻¹ dry matter) in two of three investigated cultivars independent of the sprouting level. Cold storage (4 °C) slightly enhanced SGA contents in two cultivars. Sprout control resulted in a tendentious decrease in SGA contents in a set of another three cultivars. Growing location and wet and cool seasons had an influence too. Moderate exposure to light resulted in an increase in SGA in autumn, but in a decrease in spring time. Again, cultivars tested responded differently. The addressed factors have to be considered when developing strategies in minimising SGA level in table potatoes.     

马铃薯不同品系贮藏期品质分析

马铃薯秋天入窖后,测定不同品系的还原糖含量、可溶性糖含量、淀粉含量,其结果为:还原糖含量入窖后到次年3月份逐渐升高,之后又快速下降,6-21还原糖含量最低,小白花还原糖含量最高;可溶性糖含量较稳定,只是不同品系表现趋势不同,6-21可溶性糖含量最低,1-38可溶性糖含量最高;淀粉含量也较稳定,6个品系总趋势为逐渐下降;1-38淀粉含量最高;大多数马铃薯品系的还原糖与可溶性糖呈正相关,可溶性糖与淀粉、还原糖与淀粉呈负相关。     

马铃薯不同贮藏阶段干物质变化规律研究初报

马铃薯贮藏期间(温度在1～4℃范围内)干物质含量变化呈"V"形趋势,马铃薯贮藏期间干物质含量变化与当地的气温变化一致,随着气温升高而升高,随着气温降低而降低,在1月份气温最低时马铃薯干物质含量也最低。     

马铃薯贮藏块茎低温糖化研究进展——(Ⅰ)生理生化机理

马铃薯低温贮藏造成还原糖积累是影响块茎加工品质最重要的因素,有关低温糖化机理一直是马铃薯品质改良研究的热点。本文总结了马铃薯基因型、环境因子、ABA和生物膜组成变化对还原糖积累的影响,重点从生理生化水平上探讨了块茎碳水化合物代谢路径变化与还原糖积累的关系,为抑制还原糖含量改良块茎品质打下了理论基础。     

马铃薯贮藏期腐烂原因及防治对策

马铃薯是一种高产作物,收后贮藏、稳定价格、均衡上市是提高农民收入的主要途径之一。贮藏过程中有效的控制腐烂率,更加显得重要。笔者根据定西市马铃薯生产贮藏实际情况,结合马铃薯作物的贮藏特点,提供具体的操作、管理措施,供当地马铃薯贮藏参考。     

储藏过程中不同涂膜处理方式对槟榔鲜果品质的影响

为探究不同涂膜处理对槟榔鲜果储藏过程中品质的影响,以无菌蒸馏水(CK)、壳聚糖(T₁)、壳聚糖-茶多酚-百里香酚(T₂)3组涂膜剂分别对槟榔鲜果进行表面涂膜处理后装于PE带孔包装袋中,测定13℃、65%相对湿度下贮藏40 d鲜果的品质变化规律。结果表明,T₁和T₂涂膜处理有效延缓和抑制了鲜果腐烂软化、果仁褐变、黄化、失水皱缩,货架期可从常温5 d延长至处理后35 d。相较于CK组,T₁处理有效抑制了鲜果黄化,但T₂处理综合保鲜效果最佳,除可增强鲜果初期抗氧化能力外,还可显著抑制失重率和腐烂率上升,第35天时腐烂率仅为8%。同时,T₂处理的鲜果色泽更加稳定,果仁褐变不明显。另外,呼吸强度、硬度、纤维素和木质素含量等指标的变化情况表明,储藏25 d后,T₂涂膜处理可稳定维持储藏期内鲜果生理代谢能力,保鲜效果显著优于CK组,因此T₂涂膜处理可作为一种绿色安全、经济、有效的槟榔鲜果保鲜方法。     

The Effect of High Temperature during Storage on the Vigour of Potato Mother Tubers

The aim of this work was to assess the impact of high temperature during storage and of de-sprouting before planting on the vigour of potato mother tubers of 24 potato cultivars. The study was conducted in the years 2006–2007 in the Jadwisin Branch of the Plant Breeding and Acclimatization Institute, Poland. Vigour was assessed by a field method and evaluated on a nine-point scale. It was found that mother tubers of five cultivars had maintained their growth vigour despite the high temperature in the period from autumn until the time of planting. There was no correlation between the length and mass of the emerging sprouts, plant height, mass of the above-ground part of plants, the LAI index, and the vigour of potato mother tubers. This characteristic was also not dependent on the length of the growing season of the individual cultivars.     

马铃薯块茎休眠及休眠调控研究进展

系统介绍了马铃薯块茎休眠的总体特征以及休眠块茎在细胞生理学方面的研究进展.同时还论述激素对马铃薯块茎休眠的调节作用,并提出了一些打破休眠的方法。     

Amylase Analysis in Potato Starch Degradation During Cold Storage and Sprouting

As the fourth most important food crop, potato plays a key role in food safety and economic development of the world. Harvested potato tubers can be stored for a long time, but sprouting and cold-induced sweetening (CIS) can seriously affect the quality of tubers during storage. One of the key pathways involved in CIS is starch degradation, in which both α-amylase and β-amylase play important roles. However, each amylase belongs to an extensive gene family and it is not clear which genes are the key regulators. In this study, we identified genes most likely regulating starch degradation. We first selected candidate genes from the public potato genome database and then investigated their expression patterns associated with reducing sugars and amylase activities. The results showed that the activity of α-amylase was mainly caused by StAmy23 and the activity of β-amylase was mainly caused by StBAM1 and StBAM7. In addition, α-amylase and β-amylase may play important roles in starch degradation of the tubers stored at low temperature and during sprouting, and the amylase activity may be regulated by the amylase inhibitor in cold-stored tubers.     

Demand for Processed Potato Products and Processing Quality Potato Tubers in India

Potato processing in India has shown a tremendous growth in the recent past, creating a proportionate increase in demand for processing quality potatoes. Reliable annual demand estimates of processing quality potato tubers in India were not available; hence, the current study was undertaken to provide such estimates. The study was based on a survey of 442 households in the state Maharashtra in India, which was regarded to be representative for India in the consumption of processed potato products. The annual expenditure on potato products during 2006–2007 in Maharashtra was estimated to be INR 5,254 million (€ 93.82 million), which was equivalent to 28,148 Mg of physical processed potato products and 83,333 Mg of processing quality potato tubers (0.38% of national potato production during 2006–2007, i.e. 22.09 million Mg). When the estimates were generalised to a national level, the requirement of processing-quality potato tubers in 2006–2007 was equal to 4.04% of national potato production. The forecasted annual demand of potato products in Maharashtra during 2011–2012 was 75,375 Mg and the corresponding demand of processing quality potato tubers was 230,760 Mg (0.75% of the estimated national potato production during 2011–2012, i.e. 30.89 million Mg). When generalised at national level, the demand of processing quality potato tubers during 2011–2012 was found to be 8% of the estimated national potato production.     

不同抑菌剂对马铃薯试管苗生长的影响

为降低马铃薯组培苗的污染率,试验对不同浓度的医用抗生素、防腐剂、化学农药的抑菌效果以及对马铃薯组培苗生长及生根的影响进行了研究。试验数据表明：70%甲基硫菌灵可湿性粉剂和50%多菌灵可湿性粉剂对马铃薯组培苗生产中最常见的青霉菌、细菌和酵母菌3种菌都具有较好抑制作用,并且对马铃薯试管苗的生长以及生根产生的负影响最小。     

Assessment of Antioxidant Potential of Potato Varieties and the Relationship to Chemical and Colorimetric Measurements

Potatoes are one of the main foods throughout the world contributing to the daily intake of nutrients. This work studies the relationship among some physical characteristics of tubers from 35 potato varieties, the total phenol and flavonoid content and their antioxidant potential. Some significant differences were found depending on the potato variety. Thus, Fleur Bleue, Violetta, Yona, Stronga and Flamenco tubers had the highest antioxidant capacity. This is apparently a consequence of the presence of purple and red pigments in skin and flesh. A regression model for radical scavenging activity, total phenol content and the value of coordinate a* (CIElab scale) for tuber flesh was obtained.     

Change in Some Glycoalkaloids of Potato under Different Storage Regimes

The potato (Solanum tuberosum L.) is an important food crop worldwide. Potato tubers can be stored to provide continuity of supply between production seasons, but it is important that they be stored under appropriate conditions as incorrect storage will result in deterioration in end user quality and may increase glycoalkaloid levels. We have investigated the effects of types of household storage on potato glycoalkaloid content (total glycoalkaloids [TGA]; α-solanine; α-chaconine) in Turkey. Tubers of potato cultivars (cvs.) Agria and Bettina were stored under four types of storage conditions (indirect sunlight for 10 h per day and dark storage for the remaining 14 h per day; storage under continuous fluorescent light; storage in constant darkness; storage in the dark in a refrigerator) for 56 days. Samples of tubers were taken at the beginning of the storage period and after 14, 28 and 56 days of storage for tuber glycoalkaloid measurement. Tubers stored in the three light environments showed an increase in glycoalkaloid levels; however, none of the cv. Agria tubers reached the critical level of 200 mg/kg tuber. On day 56 the TGA level of cv. Bettina tubers stored under fluorescent light reached 234.31 mg/kg.     

不同窖藏条件下马铃薯块茎营养物质含量的变化

以克新1号为供试材料,研究了4种不同窖藏条件下马铃薯块茎中干物质、淀粉、还原糖、Vc、可溶性蛋白含量的变化。结果表明:在4种不同窖藏条件下,马铃薯块茎中干物质、淀粉、还原糖、Vc、可溶性蛋白含量变化趋势相同,但变化幅度不同。窖内平均温度越高,湿度越小,块茎干物质、Vc、可溶性蛋白含量降低幅度越大,而淀粉含量降低幅度与还原糖增加幅度越小;反之,窖内平均温度越低,湿度越大,块茎干物质、Vc、可溶性蛋白含量降低幅度越小,淀粉含量降低幅度与还原糖含量增加幅度越大。     

Comparison of Two Methods For Determining the Discoloration Potential of Potato Tubers Based on Their Chemical and Biochemical Properties

The aim of this study was to compare the homogenization and visual methods that are used to determine the discoloration potential of potato tubers. Two German cultivars, Agria and Satina, and two Polish cultivars, Lena and Mors, were planted during 1998 and 1999 in Goettingen, Germany, and in Bydgoszcz, Poland. The discoloration potential of the tubers was measured after harvesting and after 6 months of storage at 4 C and 8 C. Both methods correlated significantly at harvest (0.709,P < 0.001). After storage the correlation was significant but low (r = 0.403,P < 0.001) probably because of physical changes in the tuber during storage. The visual method can be used as a fast method, especially at harvest. However, the homogenization and visual methods determine, to a certain degree, different tuber properties leading to the discoloration potential. Therefore, a complete comparison is not possible. The methods studied in this paper can complement but not substitute each other. Reliable comparisons between institutes require use of the same method to determine the discoloration potential of the tuber.     

Control of the Potato Virus X Through Application of Root Extracts of Chlorophytum nepalense to Potato Plants and Tubers

The perennial herb Chlorophytum nepalense (Lindley) Baker, widely distributed throughout the northern parts of Tripura State of India, is used traditionally by Tripuri farmers as a root extract to control dark viral necrotic lesions of sprouted potato tubers and plants. The root extracts strongly reduced infection of potato plants and sprouted tubers by Potato virus X under glasshouse conditions. The root extract was found to contain the three plant-viricidal compounds chlorogenic acid, kaempferol-3-O-(3′,6′di-O-E-p-coumaroyl)-β-d-glucopyranoside, and luteolin and suggests that the isolated compounds may have the potential to be used as natural plant-viricidal compounds.     

马铃薯块茎还原糖的测定方法比较

对传统的铜还原-碘量法和3,5-二硝基水杨酸比色法测定块茎烘干样中的还原糖进行了比较研究。结果表明,比色法的准确性和精密性均稍好于铜还原-碘量法,且操作简便、快速、环境及人为因素对其影响较小。