Processing Methods And Dietary Safety Evaluation Of Pumpkin (Cucurbita Moschata) Leaf Protein Products

This experimentation has been carried out to mainly develop an easy operating method of processing a protein concentrate, which should readily be industrialized, by using Pumpkin leaves as raw materials, analyze the nutritional components and poisonous compounds of leaf products and evaluate their dietary safety.Firstly, the comparison of the efficiency of the five kinds of techniques for preparing protein products are engaged in the experiment, which are water extraction, acid extraction, ethanol extraction, water-ethanol extraction and acid-ethanol extraction. The results indicate that the effective order of them is as the following:water extraction< acid extraction< ethanol extraction< water-ethanol extraction< acid-ethanol extraction. The results of single factor and orthogonal experiments indicate that the best conditions for concentrating proteins in Pumpkin leaves by acid-ethanol extraction were 0.4% acetic acid boiling for 3 minutes at 100℃followed by 95% ethanol extracting 5h. By the above described procedure, the protein content in pumpkin leaves was concentrated to 47.71% with 93.14% proteins recovered. Therefore, all protein products used in the followed experiments were prepared by this processing method.The results of preliminary toxic evaluation indicate that there is 10.94mg/100g total polyphenol compounds in dried full leaf samples and 2.74mg/100g in dried leaf protein concentrate samples, and there is 7.336mg/100g alkaloid in dried full leaf samples and that of 1.936mg/100g in dried leaf protein concentrate samples. These results also indicate that acid-ethanol extraction is the most effective on removing Polyphenol Compounds and Alkaloids among all over the methods studied.The LD50 of rat oral administration testified by the acute toxicity trial via four test dosage groupings was more than 20.0g/kg.bw. As that we can make a preliminary judgement from this trial that Pumpkin leaf protein concentrate prepared in this study should be innocuous according to the National Food Safety Toxicological Assessment Criteria Level 6.From a result of animal feeding tests in 7d,30d,90d and 180d, we can conclude that there was no antifeedant in the materials tested and the rats live well with thick and glossy fur. There is no significant difference between the whole leaf group, leaf protein concentrate group, grain group and the blank group in the weight increment, food utilization rate, and viscera body ratios of the rats (p>0.05, t-test). The WBC, RBC, HGB and other index of the rats in the blank group, the grain group, the whole leaf group and the protein concentrate group are within normal levels. There are no significative pathological changes between these groups through gross anatomy and histology inspection.