果蔬保鲜温度梯度试验冷库的设计与效果分析

试验以创造研究果蔬保鲜最佳温度、冷害临界温度的试验条件为目的,设计研究温度梯度库的最佳结构、工艺和技术参数,明确梯度库的温度弹性效应和温度场效应。空库运行和装入实验果蔬后梯度库温差<±0.5℃。     

Associations of psychosocial factors with fruit and vegetable intake among African-Americans

OBJECTIVE: To examine associations of various psychosocial factors with fruit and vegetable intake in African-American adults. METHODS: A cross-sectional survey of a population-based sample of 658 African-Americans, aged 18-70 years, in North Carolina. Information was collected on diet-related psychosocial (predisposing, reinforcing and enabling) factors based on the PRECEDE (Predisposing, Reinforcing, and Enabling Constructs in Educational Diagnosis and Evaluation) planning framework; demographic, lifestyle and behavioural characteristics, and fruit and vegetable intake. RESULTS: The mean participant age was 43.9 years (standard deviation 11.6), 57% were female and 76% were overweight/obese. Participants expressed healthy beliefs regarding many of, but not all, the psychosocial factors. For example, although half of the respondents believed it is important to eat a diet high in fruits/vegetables, only 26% knew that >or=5 daily servings are recommended. The strongest associations of the psychosocial factors with fruit/vegetable intake were for predisposing factors (e.g. belief in the importance of a high fruit/vegetable diet and knowledge of fruit/vegetable recommendations) and one reinforcing factor (social support), with differences between the healthiest and least healthy responses of 0.5-1.0 servings per day. There was evidence of effect modification by gender in associations between psychosocial factors and fruit/vegetable consumption (e.g. self-efficacy was only significant in women), with higher intakes and generally healthier responses to the psychosocial variables in women than men. CONCLUSIONS: Interventions to increase fruit/vegetable intake in African-Americans may be more effective if they focus primarily on predisposing factors, such as knowledge, self-efficacy and attitudes, but not to the exclusion of reinforcing and enabling factors. The psychosocial factors that are targeted may also need to be somewhat different for African-American men and women.     

Correlates of fruit and vegetable intake among Norwegian schoolchildren: parental and self-reports

OBJECTIVES: To identify correlates of 6th and 7th graders' (age 10-12 years) fruit and vegetable intake, to investigate parent-child correlations of fruit and vegetable intake, and to compare parents' and children's reports of children's accessibility, skills and preferences with respect to fruit and vegetables. DESIGN: The results presented are based on the baseline survey of the 'Fruits and Vegetables Make the Marks Project', where 38 schools participated. SETTING: Fruit and vegetable intake was measured by food frequency questions. Theoretical factors, based on Social Cognitive Theory, potentially correlated to intake were measured, including behavioural skills, accessibility, modelling, intention, preferences, self-efficacy and awareness of 5-a-day recommendations. SUBJECTS: In total, 1950 (participation rate 85%) 6th and 7th graders and 1647 of their parents participated. RESULTS: Overall, 34% of the variance in the pupils' reported fruit and vegetable intake was explained by the measured factors. The strongest correlates to fruit and vegetable intake were preferences and accessibility. The correlation between the children's and their parents' fruit and vegetable intake was 0.23. The parents perceived their children's accessibility to be better than what was reported by the children (P<0.01), while the children reported their skills to be better than what was perceived by their parents (P<0.01). CONCLUSION: The results from this study clearly point to a need for nutrition interventions aimed at parents. An important next step will be to investigate whether the identified correlates predict future fruit and vegetable intake, and whether they mediate any changes in intake in an intervention study.     

A school salad bar increases frequency of fruit and vegetable consumption among children living in low-income households

OBJECTIVE: To measure change in fruit and vegetable (F&V) consumption among elementary-school children after the introduction of a salad bar programme as a lunch menu option in the US Department of Agriculture's (USDA) reimbursable lunch programme in Los Angeles Unified School District (LAUSD). DESIGN: A cross-sectional sample of children was interviewed before and after a salad bar intervention (1998 and 2000, respectively) utilising a 24-hour food recall questionnaire. Frequencies of F&V consumption were calculated. SETTING: The evaluation took place in three LAUSD elementary schools participating in the salad bar programme and the USDA reimbursable lunch programme. SUBJECTS: Three hundred and thirty-seven children in 2nd-5th grade (7-11 years old). RESULTS: After the salad bar was introduced, there was a significant increase in frequency (2.97 to 4.09, P < 0.001) of F&V consumed among the children studied. The increase in frequency of F&V consumed was almost all due to an increase during lunch (84%). Mean energy, cholesterol, saturated fat and total fat intakes were significantly lower in the children after the salad bar was introduced in the schools compared with the intakes in the children before the salad bar was introduced.Conclusion: A salad bar as a lunch menu option in the USDA reimbursable lunch programme can significantly increase the frequency of F&V consumption by elementary-school children living in low-income households.     

Disease and injury among participants in the Agricultural Health Study

The Agricultural Health Study (www.aghealth.org) is a cohort of 89,658 pesticide applicators and their spouses from Iowa and North Carolina assembled between 1993 and 1997 to evaluate riskfactorsfor disease in ruralfarm populations. This prospective study is just now reaching sufficient maturity for analysis of many disease endpoints. Nonetheless, several analyses have already provided interesting and important leads regarding disease patterns in agricultural populations and etiologic clues for the general population. Compared to the mortality experience of the general population in the two states (adjusted for race, gender, age and calendar time), the cohort experienced a very low mortality rate overall and for many specific causes and a low rate of overall cancer incidence. A few cancers, however, appear elevated, including multiple myeloma and cancers of the lip, gallbladder, ovary, prostate, and thyroid, but numbers are small for many cancers. A study of prostate cancer found associations with exposure to several pesticides, particularly among individuals with a family history of prostate cancer. Links to pesticides and other agricultural factors have been found for injuries, retinal degeneration, and respiratory wheeze. Methodological studies have determined that information collected by interview is unbiased and reliable. A third round of interviews scheduled to begin in 2005 will collect additional information on agricultural exposures and health outcomes. The study can provide data to address many health issues in the agricultural community. The study investigators welcome collaboration with interested scientists.     

果蔬三维切丁机设计与试验

为了提高国产切丁机的切削质量和切削效率,设计了一种新型果蔬切丁机.该机采用旋转推进器送料,离心切削法切片,圆盘格栅刀切丝,最后由切丁条刀切丁的三维切丁技术.论文阐述了切丁机结构组成及工作原理,并以马铃薯为切削对象,进行了物料在离心切削滚筒内的受力分析计算,确定出切削滚筒最小工作转速为133.3 r/min;对所切物料丁断面曲线方程分析,得出切丁断面具有3种不同形状,通过比较不同离心切削滚筒与切丁条刀转速比条件下的切丁断面形状及偏差,得出其最佳速比为0.17.样机切削性能试验表明:切出的15 mm× 15 mm×15 mm和20 mm×20 mm×20 mm马铃薯立方块形状规整,其相对偏差分别为11.7％、12.7％,均小于15％,达到了预期目标,为新型果蔬三维切丁机的研制提供了参考.     

光对采后果蔬叶绿素降解动力学研究

叶绿素对光不稳定,易降解,为探讨引起该类色素降解的主要因素,并在生产、加工及贮藏中予以克服和避免,更好地保证产品在货架期内的感官品质,提高经济效益。该试验利用紫外分光光度计、全自动色差计(CIE-L*a*b*)和高效液相色光谱法定量分析叶绿素光降解的变化情况,并对叶绿素光降解动力学过程进行了分析。结果表明:叶绿素光降解反应符合一级动力学模型;紫外线对叶绿素有很强的破坏作用,可见光中蓝光、红光对该色素降解作用次之,而红外线对叶绿素破坏作用较小;光照强度为500、1000、1500、2000、2500、3000、3500、4000、4500、5000 lux,温度为25℃的条件下,叶绿素降解半衰期分别为16.9、14.1、11.5、9.8、8.8、8.2、7.1、6.0、5.2、4.0 h;相同条件下叶绿素a的降解速率约为叶绿素b降解速率的3～4倍;叶绿素在温度60℃以下降解不明显;氧气在叶绿素光降解过程中有着非常重要的作用。本试验结果对绿色果蔬包装材料的选择和产品感官品质控制有一定的参考价值。     

Ethnic differences in 1-year follow-up effect of the Dutch Schoolgruiten Project - promoting fruit and vegetable consumption among primary-school children

OBJECTIVE: To evaluate the effect of a primary school-based intervention providing free fruit and vegetables (F&V), separately for children of Dutch and of non-Western ethnicity. SETTING: Primary schools in two regions (west and east) in The Netherlands. DESIGN AND METHODS: Participating schoolchildren and their parents completed questionnaires at baseline and 1 year later, including questions on usual F&V intake, potential determinants and general demographics. Primary outcomes were the usual fruit intake and the usual vegetable intake as assessed by parent- and child self-reported food frequency measures. Secondary outcome measures were child- or parent-reported taste preference, knowledge of daily recommendations, availability, and accessibility for fruit intake. Multilevel regression analyses were used to assess differences at follow-up adjusted for baseline values between the control and intervention group using both child and parent reports. SUBJECTS: Five hundred and sixty-five children of Dutch ethnicity and 388 children of non-Western ethnicity (mean age 9.9 years at baseline) and their parents. RESULTS: Children of non-Western ethnicity in the intervention group reported a significantly higher vegetable intake (difference = 20.7 g day-1, 95% confidence interval (CI) = 7.6-33.7). A significant positive intervention effect was also found for fruit intake for children of Dutch ethnicity (difference = 0.23 pieces day-1, 95% CI = 0.07-0.39). No significant effects in intake were observed based on parent reports. Significant positive intervention effects were also found for perceived accessibility among children of non-Western ethnicity, as well as for parent-reported taste preference of their child among children of non-Western ethnicity and boys of Dutch ethnicity.CONCLUSION: Providing children with free F&V had some positive effects on child-reported intakes and important correlates of intakes.