さつまいもの加熱調理直後、冷蔵保存及び再加熱によるレジスタントスターチ量の変化

Resistant starch（RS）escapes digestion until reaching colon and acts like dietary fiber. Recently,many studies suggest that RS, in addition to dietary fiber, may be beneficial for our health. Sweet potatoes（Ipomoea batatas）is very common carbohydrate source in Japanese diet. Japanese people cook and eat sweet potatoes by boiling, steaming, baking or other cooking methods. RS content might vary when sweet potatoes are cooked by different methods, kept in refrigerator after cooking and reheated. Therefore, the purpose of this study was to investigate effects of cooking, cooling and reheating on resistant starch contents of sweet potatoes. Materials & Methods: Potatoes were cooked by three different methods (boiling, steaming or baking) until they reached the same degree of tenderness. The temperature of sweet potatoes was also monitored duringcooking. RS contents of immediate after cooking, freezing 24hour and reheating of sweet potatoes were analyzed. Results & Findings: Among three cooking methods, boiling was the highest RS contents and baking was the lowest. RS contents of all cooking methods were raised after 24hr freezing. However, RS contents of these cooking methods altered differently after reheating sweet potatoes. These results showed that cooking methods might affect RS contents of sweet potatoe

Effect of grass mulch application on tubers size and yield of ware potatoes in organic farming

The aim of this experiment was to evaluate influence of mulching on the tuber yield and on the number of ware potatoes. In organic farming grass mulch for potatoes was used in 2008. For the experiments different ways of mulching (grass mulch after planting, grass mulch after second hoeing) were used and compared with bare soil (control variant). The results showed that grass mulching had positive effect on the yield of ware potatoes and some of the yield-forming components. The yield of ware potatoes was significantly higher by 9.3 t/ha in comparison with control variant. The highest number of ware potatoes was found out in the variant with grass mulch after planting

Potato Marketing – Factors Affecting Organic and Conventional Potato Consumption Patterns

In producing potatoes the treatment for disease and pests could be more difficult and costly for organic producers than for conventional. Hence, consumers’ attitudes and willingness to pay for organic potatoes need to be considered in a grower’s choice of production technologies. A bivariate probit model and cluster analysis were applied to survey data to evaluate factors that influenced Germany consumers’ consumption patterns for conventional and organic potatoes. The results show that consumers associate organic potatoes with healthy ingredients, trustable origin and food safety. But a lack of varieties and inferior appearance of organic potatoes limit consumer interest in the organic products. With regard to socio-demographics, consumers with higher education level and with children in the household tend to consume organic potatoes more often than consumers with lower education and no children in the household. Cluster analysis results group potato consumers into three different market segments: “Trusting of industry”, “Health-oriented” and “Price-oriented” segments. These results suggest adopting different marketing strategies to promote fresh potatoes to the different market segments.organic, potatoes, consumption patterns, Food Consumption/Nutrition/Food Safety, Marketing,

THE INFLUENCE OF MICROWAVE OVENS ON THE DEMAND FOR FRESH AND FROZEN POTATOES

Growth in the number of homes with microwave ovens has changed food preferences and preparation methods. The objective of this study was to determine the impact that microwave oven ownership has had on the demand for fresh and frozen potatoes. Using data from the 1970-88 period, demand equations were estimated for fresh potatoes, frozen potatoes in the retail market and frozen potatoes in the food service market. Results indicate that increases in the percentage of homes that own microwave ovens have shifted demand outward for fresh potatoes but inward for frozen potatoes. If potato processors can develop a microwave frozen French fry that satisfies consumers, microwave ovens could boost the demand for frozen potatoes along with the increase in demand for fresh potatoes.Demand and Price Analysis,

Chemical Sprout Control of Alaska Potatoes.

POTATOES sprout in 11 to 15 weeks after harvest if placed in storage where 'temperatures average 40° F or above. Prior to this, growth regulating substances within the tubers prevent sprouting. If potatoes are stored at room temperature (70° F or higher) their dormant period will be shorter, although differences in varieties are observed. Varieties also differ in habit of sprout growth*. Some develop long sprouts that are relatively easy to remove. Even so, a new crop of sprouts will grow again from the same eyes if storage temperatures remain above 40oF for ten days or more. In addition to the expense of desprouting, potatoes lose weight and their market appeal. Potatoes can be and are stored at 30° to 36° for nearly a year with very little sprouting. Cold storage at this temperature range has some disadvantages. For example, starches are converted to sugar within the tubers. These sugars give cooked potatoes a sweet taste objectionable to some people. Potatoes with a high sugar content are not suitable for chipping and french frying. Sometimes they can be reconditioned by storing at 60° to 70° for a month or more but this warmer environment starts sprouting. Potatoes sprouting extensively in bins (as illustrated in Figure 1) cannot be ventilated properly because sprouts fill the air spaces between tubers. Lack of air movement through the bin causes a low oxygen supply and black heart or b1ack patches soon appear within tubers (Figure 2). Sprouting is costly to Alaskans in that it reduces the number of potatoes meeting U.S. No. 1 grade and therefore reduces farm income.Sprouting is costly to Alaskan's potato industry because it weakens Alaska's competitive position for summer markets. Summer im}:orts of dormant potatoes often capture a large segment of the Alaskan potato market. When these studies were begun, workers in other regions (2, 4, 5, 9) had demonstrated several methods of chemical sprout control. These methods included field spraying of tops, dusfng or dipping of tubers moving into storage, and gas treatment with volatile substances distributed within binned potatoes. Chemicals that had given the best control were methyl ester of naphthaleneacetic acid (MENA), indoleacetic acid (IA), maleic hydrazide (MH) and isopropyl N-(3 chlorophenyl) carbamate (CIPC). In other states MH has become so popular that it has been recently sprayed from an airplane ( 1) and CIPC has been released as an aerosol or vapor (6) within the storage. Some evidence has been presented (3) showing that healing of tender skins and healing of tuber bruises is delayed by sprout inhibitors. Unwashed potatoes frequently carry enough mud or wet soil into storage to inhibit good air movement through the bin. While washing prior to storage eliminates this particular problem, little is known about the storage characteristics of washed treated tubers (10). The objectives of these sh1dies were to learn (1) if sprout inhibitor chemicals used in other regions also inhibit Sf)routing of potatoes grown in Alaska's environment, (2) what effect snrout inhibitors have on yield and quality, (3) when and at what rate the chemical should be applied, (4) how sprout inhibitor treated potatoes store at different temperatures, (5) if washing fieldtreated potatoes prior to storage influences keeping ability or modifies sprout inhibitor action

Cultivation and analysis of anthocyanins containing-, blue potatoes

Anthocyanins, as secondary plant substance in different agricultural crops such as potatoes and cereals have positive effects on health due to their antioxidant capacity. Therefore food industry, nutritional medicine and consumers have an increasing interest in these crops. The objectives of the interdisciplinary research project (AGIP) starting in march 2006 are ascertainment and assessment of the impact of different agricultural production processes and production intensities. Furthermore, the impact of different ways of food preparation concerning anthocyanin content and antioxidative capacity in selected cultivated plants will be tested. Main focus will be on potatoes due to the fact that potatoes as a staple food are consumed in large quantities. Therefore potatoes can be an important quantitative source for anthocyanins

Wireworm Control using Fodder Rape and Mustard – evaluating the use of brassica green manures for the control of wireworm (Agriotes spp.) in organic crops

In a field experiment at ADAS Pwllpeiran in 2001, brassica green manures were grown for 6 weeks and dug in before planting King Edward potatoes, to see if they suppressed wireworm in the crop. There was a trend for potatoes grown after mustard to suffer less damage from both wireworms and slugs than potatoes grown after fodder rape or no green manure, but the differences were not significant. Further trials, with longer green manuring periods, are needed to establish if there is a benefit, and whether the breakdown products of brassica green manures are toxic to wireworms

DETERMINANTS OF CONSUMERS' PURCHASE DECISION FOR MAINE ROUND WHITE POTATOES

Potatoes are marketed by type (i.e. round white, russet, red, etc.), rather than by variety. However, the round white varieties currently marketed by the Maine potato industry are known to differ considerably in terms of product characteristics. This study was designed to test the hypothesis that consumer acceptance of potatoes in home use varies by variety and to quantify how their level of acceptance and other characteristics impact their repurchase decision. A discrete choice model was used. The results indicated that consumers do differentiate round white potato varieties based on the performance of the potatoes in home use. Their willingness to repurchase the round white potatoes is affected by the variety used and the overall serving quality of the potatoes in home use.Consumer/Household Economics,

ALTERNTIVE PROTECTION OF BIOPOTATOES IN ORGANIC FARMING

There were tested water extracts from Syringa vulgaris and Pyrethrum parthenium. They did not prove significant differences of decrease of the air attack of Colorado potato beetle (Leptinotarsa decemlineata), the activity of eggs – laying and the occurrence of larvae in comparison to the control. Interesting trends of lower-eggs lying and a lower larvae occurrence were discovered. The liquid spray against the late blight (Phytophthora infestans) did not significantly decrease neither occurrence of late blight or the yield. The production of the bio-potatoes is only 0,2 % of all potatoes production in the Czech Republic. The aim of this experiment was to try alternative methods of regulation of Colorado potato beetle and late blight (the biggest harmfull organisms of potatoes). For biological agriculture could be also suitable water extracts. These are possible to use as protection of potatoes against unfavorable factors (Colorado potate beetle and late blight) and increase yield and quality of production

Comparing low rate copper formulations against Phythophthora infestans in potatoes

Between Dutch organic growers the late blight problems lead to discussions in which a temporary registration of copper products is also suggested. Some growers do not want any pesticides at all, while others see that biological potatoes from abroad are sold in the super markets in years when Dutch organic potatoes are scarce. Those potatoes come from countries, where copper products are allowed. They speak about competition falsification. In the research program to stimulate organic production the choice is made to also investigate the efficacy of copper and other products that are allowed in surrounding countries in organic farming. In the experiment of 2008 6 different copper containing products are tested