Study On Key Quality And Safety Technologies For Controlling Pancake Production Based On Leavening Agents Combined Pulsed Light Sterilization

Pancake, one of the traditional grain foods, was baked by fermented or unfermented batter wich was ground by grain and cereals. More currently it was traditional natural workshop fermentation that produced pancake, natural fermented problems like process being easier to microbial secondary pollution, low productivity, unstable product quality, worrying food quality and safety were prominent, it was imperative to seek technical solutions to these problems.Microbial control in the process of batter fermention was research core based on influencing quality of northeast pancake by enrichment culturing and lineation separating, the dominant species in pancake fermented batter which isolated and screened preliminarily by colony morphology, color, size and rescreened by physiological and biochemical tests, tolerance test were identified by VITEC-2 compact microbial identification system; Directed vat set starter was made by freeze drying technology; Screened strains were mixed by the electronic nose and Pancake flavor differences between fermentation with agent and natural fermentation were analyzed by SPME-GC-MS(solid phase micro extraction- gas chromatography- mass spectrometry) analysis technology, which laid the foundation for pancake, it had characteristic of unique flavor quality, made by mixed directed vat set starter; bacteria, mold, E.coli were srerilized by advanced pulsed light in order to control hazardous microorganisms and improve edible safety.The experimental results were as follows1 Nine strains lactic acid bacterium and eleven strains yeasts were got from fermented pancake batter, R2 and R8 lactic acid bacterium and Y8 yeasts which had good fermentation performance and outstanding flavor were used pancake dedicated complex microbial agents, R2 was Leuconostoc mesenteroides, R8 was Pediococcus pentosaceus, Y8 was Saccharomyces cerevisiae. Through single factor and response surface methodology of experiments design optimization parameters, the formulation of cryoprotectant in the process of composite fermenting agent was Trehalose 1.38 %, sodium glutamate 4.80 %, sucrose 13.80 %, skim milk 13.50 %. Under optimized conditions, the survival rate can reach 88 %.2 Composite fermentation agent combination which was close to naturally fermented pancake flavor was determined by electronic nose, on the premise of Lactic acid bacteria and yeast in the ratio of 1.5:1, it was closest to fermented naturally one Pentosaceus and Leuconostoc bacteria in ratio of 1:1.3 The SPME-GC-MS(solid phase micro extraction- gas chromatography- mass spectrometry) analysis technology showed that the natural fermentation pancake and the leavening agents one contained 39 and 34 kinds of volatile substances respectively, including alcohols, acids, esters, aldehydes, ketones and aromatic compounds and so on, whereas the unfermentation pancake contained 21 kinds of volatile substances. Leavening agents and natural fermentation pancake had almost same kinds of substances and similar tastes,and there were increased variety and quantity of substances than the unfermented one.4 Bactrria, mould, E.coli on pancake were killed effectively by pulsed light to improve edible security, under these conditions, 1.65 log mould reduction can reached by pulsed light, approximately 97.7 % mould being inactivated, 2.15 log E.coli reduction could reached by pulsed light, 2.3 log bacteria reduction could reached by pulsed light. The shelf life of pancake was predicted at pulse energy 500 J, pulse number 30, pulse distance 10.9 cm, the results showed that shelf life of pancake could be prolonged 3 months.