Spoilage Microorganisms In Traditional Fermented Flour Products And Relevant Natural Inhibitors

There is a wide variety of traditional fermented flour products in our country which are mainly consist of Steamed buns、bread flowers and Steamed stuffed buns, and they are staple in northern china, at the same time and Steamed buns is the representative of traditional fermented flour products. The yearly consumption of Steamed buns in our country is more than12million tons, and about70%of the wheat flour is used for steaming Steamed buns in the northern region. Because of its rich nutrition and high moisture content, steamed buns are easily to breed spoilage microorganisms and lead to its spoilage, which not only brings huge economic losses to the manufacturers but also threatens human health seriously through microbial secondary metabolites. At present, food safety issues caused by using chemical preservatives make the natural preservatives increasingly favored by consumers.This research has been focused on identifying spoilage microorganisms that lead to the metamorphism of traditional fermented flour products and investigating a new natural method to prevent the metamorphism of traditional fermented flour products. Moldy steamed buns with different manufacturers are regarded as research object. Firstly, determine main spoilage microorganisms that lead to steamed buns metamorphic. Secondly, study the inhibition of34kinds of traditional Chinese medicine extract. Thirdly, optimize the extraction process of Coptis chinensis Franch and Scutellaria. Lastly, make use of their crude extracts to investigate actual antimicrobial effect, provided some new materials and ways for the development of new natural preservatives. In this paper the main results are as follows:1. The separation, purification and preliminary identification of spoilage microorganisms in Steamed buns. The results showed that the main microorganisms that lead to Steamed buns’spoilage are six kinds of fungi, and they are identified as Penicillium, Aspergillus flavus, Aspergillus niger, Rhizopus nigricans, Trichosporoncutaneum1and Trichosporoncutaneum2.2. Study on the antibacterial effects of34extracts of traditional Chinese medicine. The results showed that ethanol extract of12kinds of Chinese medicines including scutellaria, Rhizoma Coptidis, Treats, Zingiber officinale Rose, Galangal, Atractylodes, Eucommia, Gentian, Agastache, Cnidium monnieri (L.)Cuss., Artemisia argyi Levl. et Van. and Illicium verum Hook. F. has different degrees of inhibition on one or more of six kinds of fungi, and all of them have inhibition on Trichosporoncutaneum1; while ethanol extract of the other22kinds of Chinese medicines including Folium Nelumbinis, Angelica dahurica Benth.et Hook, Mosla chinensis Maxim, ArtemisiacapillarisThunb.,Sweet Wormwood Herb,Dendranthema indicum,Belamcanda chinensis (L.) Redoute,Aitractylodes lancea (Thunb.) DC.,Cortex dictamni,Lonicera japonica Thunb.,Sophora flavescens Ait.Stemona sessilifolia (Miq.) Miq.,Taraxacummongolicum Hand.-Mazz., Houttuynia cordata Thunb., Rehmannia glutinosa Libosch,Ligustrum lucidum Ait.,PlantagoasiaticaLt;PlantagodepressaWilldi,Belamcanda chinensis (L.) Redoute,Dried Tangerine Peel,Poria cocos Wolf,Astragalus membranaceus (Fisch.) Bunge., Mentha haplocalyx Briq. only has weak or even has no inhibition on obtained fungi; both Scutellaria and Rhizoma Coptidis have different degrees of inhibition on six kinds of obtained fungi and the overall inhibition effect is good.3. Study on the best extraction process of Scutellaria. The results indicated that the best extraction process is as follows:The extraction time is3h, ratio of solid to liquid isl:4.5, extraction temperature is66.7℃, and the alcohol concentration is62.7%.4. Study on the best extraction process of Coptis. The results indicated that the best extraction process is as follows:The extraction time is2h, ratio of solid to liquid is1:4.6, extraction temperature is30.5℃, and the alcohol concentration is49.4%.5. The durability test of steamed bread with the extract of scutellaria and Coptis. The results showed that antimicrobial packaging with crude ethanol extract of Coptis and Scutellaria obviously prolonged shelf life of steamed bread. When stored under the condition of40%relative humidity and28℃, the shelf life of steamed breads that were dealt with ordinary packaging, packaging with Scutellaria extract, packaging with Coptis extract are2,3,4days.