Germinated Wheat Mildew And Its Effect On Main Quality During Storage

The embryos of germinated wheats have already broken through the seeds coat, thiswould enable to moisture absorption easier from the environment in the storage process, andthus cause the enhancement of seed moisture, microbial vigorous activity and easier infectionby mold as well, all that will eventually lead to reduce its storage stability. In this paper,Zhengmai366(a red wheat species of strong gluten) and the Aikang58(a white one of weakgluten) are both worked as the research objects, we investigated the moisture absorption andstoring quality variation of the two germinated species under various relative humidity andtemperatue. The storing seeds stability of different germinating extent and diverse moistureare also studied and the effect of high temperature and microwave treatment on bioactivity ofAikong58was carried out as well. Many first hand data were obtained about the qualitydeterioration of germinated wheat in the period of storage, which could be good reference forits safe storage and quality analysis.The study on moisture absorption of germinated wheat and the process of qualitydeterioration showed that the higher relative humidity the germinated wheats are stored under,the more intense moisture absorption they show. The germinated wheat had higherequilibrium water content at a lower environmental temperature and certain of humidity. Thechange in fatty acid value, microbial activity, germination rate and protein contend ofgerminated wheat showed a similar trend in the the process of moisture adsorption, whichchanges more significant as the relative humidity of storred environment increased. Thestorage quality of germinated wheat did not change much after storing60days under RH70%.However, obvious mold could be observed on the germinated wheat after9days of storageunder RH90%, also the fatty acid value and microbial activety increased significantly, thebudding rate dropped to less than20%and some proteins were biodegraded, the edible qualityhas lost. The moisture absorption of germinated wheat is greater than the normal wheat at thesame temperature and humidity, and so its quality changed faster than the normal; Soft glutenand White Wheat had more moisture absorption than the red wheat in strong gluten, thereforethe quality easier to change. High humidity of RH90%, the water-soluble protein ingerminated wheat changes significantly than its salt soluble proteins, but protein in the normalwheat does not change significantly in the short storage period.Study about storage stability of germinated wheat with different water content shows that: all the detection indicators of germinated wheat with low water content changed little, but thehigher the moisture, the more obvious changes in storage quality. With the increase ofmoisture, microbial activity and fatty acid value gradually increased, respiration enhanced,mildew level deepened and the germination rate reduced。Microbial activity of germinatedwheat with bud of15.5%moisture content was exuberant after storage of21days，and totalnumber of mildew increased by1.35×105cfu/g. At the same time，its increase in theamount of fatty acid value was respectively14.3times and3.4times higher than that of thesame nature germinated wheat of13.2%and14.5%moisture content. Compared with thegerminated wheat, the basal value of fatty acid and respiration of germinated wheat with budis higher,and rises faster during storage.The impact of microwave and high temperature treatment on biological activity andstorage quality of germinated wheat shows that: The germination rate of reduced, fatty acidvalue gradually increased, respiration and microbial activity weakened, after microwave andhigh temperature treatment on germinated wheat. The15.2%of initial moisture in germinatedwheat could be decreased under the safe moisture of12.5%either by upper65℃more than0.5h or50s of microwave. Both ascending temperature and prolonged time could cause aserious impact of bioactivity, and the16.7%and9.5%of germinated ratio were foundrespectively by80℃/1h and50s of microwave treatment. Although microwave treatmentcould reduce the moisture content,biological respiration and microbial activity of germinatedwheat in a short time, it would cause greater impact on germinated wheat protein, what ismore, protein denaturation of germinated wheat would appear after treatment with more than20seconds. The longer high temperature treatment, the lower the moisture content, but therewould not lead obvious effect on germinated wheat protein, for example, there was nodestructive effect on the protein with treatment at95℃for1hour.