提高β－胡萝卜素保存率的研究

研究了胡萝卜制汁过程中造成β－胡萝卜素损失的因素，分析了去皮、热烫。脱气、杀菌等主要加工工序对β－胡萝卜素保存率的影响，筛选出β－胡萝卜素损失最小的最佳工艺条件，使β－胡萝卜素保存率可达８２．３％。

Determination of 3H and 14C in Organic Sample after Separation through Combustion Method

The Environmental program of the Cernavoda NPP （nuclear power plant） is based on the analysis of environmental samples： airborne, TLDs （thermoluminescence dosimeters）, water, deposition, soil, grass, sediment, fish, milk, meat, eggs, grains, fruits and vegetables, using determination of 3H and 14C, gross alpha/beta and gamma spectrometry measurement techniques. This Program is a legal constraint for nuclear utilities and it is approved and supervised by the regulatory body. Besides, the actual legal requirements, Cernavoda NPP participates in a CANDU （Canadian Deuterium Uranium） Owners Group Project （COG HS ＆ E-304） in order to implement the new standard CAN-CSA 288.1-08 for derived emission limits using results of measurements for OBT （organically bound tritium） concentrations in plant and animal products. The method for determination of 3H and 14C in organic samples after separation through non-catalytic combustion by flame oxidation is performed in Sample Oxidizer 307 equipment. Average values for total tritium activity concentration in fish samples of 21 ± 2 Bq/kg fresh weight were determined. Results for 14C have an average value of 327 ± 26 Bq/kg-C in fish from Danube-River and 315 ± 25 Bq/kg-C in fish from lakes. The average values for 14C activity concentration in vegetables samples from Cernavoda and Seimeni areas are about 338 ± 27 Bq/kg-C.

Statistical Analysis of Regularity of Pesticide Residues in Vegetables Produced in Inner Mongoli

[Objective]The paper was to study regularity of pesticide residues in vegetables produced in Inner Mongolia.[Method]Mathematical statistic analysis was carried out on 6 800 samples of veggies,fruits,leguminous vegetables,nuts and seeds produced in Inner Mongolia.[Result]The dominated vegetables in Inner Mongolia were green leafy vegetables,solanaceous vegetables and melon vegetables,and their yields accounted for 70%of the total vegetables production.Since 2003,with the rapid increase of detected vegetable numbers,the status of vegetable quality safety had entered into a new stage of sustainable steady after a rapid decline or periodic fluctuation,and the differences in safety levels were obvious,of which the range of exceeding standard rate of pesticide residues in solanaceous vegetables,melon vegetables and leguminous vegetables(about 55%of the total vegetables)was under 2%,with average values of 1.1%,1.6%and 3.1%,respectively.They belonged to stable type.The exceeding standard rate of pesticide residues in green leafy vegetables and Chinese cabbage group(about 30%of total vegetables)presented a decreasing trend year by year,wondering in the range of 7%-10%.They belonged to main risk type.The time period of exceeding standard of pesticide residues in root vegetables and cole vegetables was under predictable,and its exceeding standard rate in some years was over 5%(amplitude variation is over 15percentage points).They belonged to random risk type.The kinds of pesticides,which exceeding standard rate in vegetables were relatively intensive,presented variance in different vegetable species.70%of the pesticides belonged to intermittent over-limits and the probability was below 5%.About 20%tradition pesticides often exceeded standard and their probabilities were over 30%.The exceeding standard of organophosphorus and carbamates pesticides in vegetables presented a decreasing tend,while the risk of some new pesticides containing nitrogen element and high effective pyrethroids showed an increasing tendency.[Conclusion]The paper provided decision making services for agricultural management departments.

Estimating the Fresh Vegetables Demand System in Jordan： A Linear Approximate Almost Ideal Demand System

The main objective of this research is to estimate the different types of demand elasticities for the main fresh vegetables consumed in Jordan. The estimated elasticities can be used to measure the impacts of agricultural policies and can be used to predict future consumption in the context of food security in terms of access, availability, stability, and food quality. The reported demand estimates were obtained through the estimation of a Linear Approximate Almost Ideal Demand Systems （LA/AIDS） for Jordan fresh vegetable crops demand system using the most recent cross-sectional data of household expenditure survey in 2005. A censored regression method for the system of equations was used to analyze fresh vegetables consumption patterns. This method allows for inclusion of a large number of zero consumption for some foods through two-step demand system estimation. All of the own-price demand elasticities have the correct negative signs and statistically significant. According to the expenditure elasticity, tomato, cucumber, and potato are the necessity goods. The mean budget shares indicate that consumers spend 30 percent of their allocated budget to vegetables on tomatoes and potatoes. The green bean elasticity is the highest indicating that demand for beans is highly responsive to any changes in the price. The expenditure elasticities reveal that the demand on all vegetables is expected to grow over the coming few years. High own-price elasticities of all vegetables studied suggests that any changes in the prices of these crops could bring about a significant shift in fruits and vegetable constanption patterns.