Separation And Inhibition Of The Spoilage Moulds In Cantonese-style Moon Cakes

Cantonese-style moon cakes are traditional bakery foods in South China area, whichhave unique flavor, variety, rich in nutrients. However Cantonese-style moon cakes are a kindof high-fat and high-sugar foods, easily oxidized and spoilaged. Cantonese-style moon cakesare rich in nutrients, so it is easy to the breeding of microorganisms and moldy. Therefore, ithas great benefit to the Cantonese-style moon cakes production by using various preservationmethods, especially using mould inhibitor to control the growth and breeding of moulds. Thefungal species that cause Cantonese-style moon cakes moldy will be different in differentregions. This research began with separating the fungal species of Guangdong spoiledCantonese-style moon cakes moulds, then finding the suitable ways to inhibit the mouldswhich live in Guangdong area or live in the areas with similar climate of Guangdong.9strains of moulds marked No.1, No.2, No.3, No.5G, No.6, No.9, No.W1, No.W2andNo.R1were separated and purified from the spoiled Cantonese-style moon cakes (which werespoiled in Guangdong). The identification of moulds was studied. According to the singlecolony’s modality and color, microscope observation results on spore and myceliummorphological characteristic. The results showed that, No.1, No.2, No.6, No.9No.W1,No.W2were Aspergillus; No.3was Penicillium; during the preliminary identification, No.5Gand No.R1are failed to identify which kind of fungal species they are. These results were inaccord with the general research, that Aspergillus and Penicillium are the main fungal speciesleading to the bakery foods spoilage.By studying a variety of different types of mould inhibitors on the antifungal activity ofthe target moulds, and ultimately obtained5kinds of mould inhibitors. Sodiumdehydroacetate, Natamycin, sodium paraben complex, cinnamon essential oil and garlicessential oil were chosen as the better inhibitors to the moulds. The Minimum inhibitoryconcentrations (MIC) of these5mould inhibitors were studied. The results showed that:Natamycin was used in spray form of mould inhibitor, and its’ antiseptic effect is better. Theoptimized inhibitor complex was determinted by Response Surface Methodology (RSM),0.0160g/100mL Sodium dehydroacetate,0.0160g/100mL sodium paraben complex,0.0376%cinnamon essential oil. The anti-mould effect of the optimized inhibitor complex was proved by Oxford plate validation test.Using this optimized inhibitor complex to the anti-spoilage of the Cantonese-style mooncakes; Natamycin used in spray form, its’ dosage is0.1g/kg. Packaged moon cake samplesstore in temperature of30±1℃, humidity of90±1%of the artificial climate chamber to speedup the process of mould. The samples especially for the red bean paste material which rawmaterials contain moulds but without adding mould inhibitors, had a serious deterioration in15-30days. Adding mould inhibitors, even if the raw materials contain moulds in theaccelerated deterioration of conditions, the moon cakes can still be edible save up to30days.Storing samples with deoxidizer containing less mould, moon cakes skin contain moremoulds than moon cakes stuffing. Due to the high osmotic pressure has certain inhibitoryactivity, the samples contain less mould for storing15days than the beginning. But addingmould inhibitors extend the product shelf life. Nevertheless, along with the longer shelf time,adding mould inhibitors can greatly guarantee the shelf life of Cantonese-style moon cakes.