Study On The Processing Technology Of Tremella Crispy Biscuit And Digestive Characters Of Starch

Tremella (Tremella fuciformis Berk.) is a traditional medicinal and edible fungus, containing polysaccharide, dietary fiber, flavonoids and other active ingredients, having the effect of antioxidant, anti-tumor, anti radiation, prevent diabetes, obesity and so on, which edible value and medicinal value are high. At present, tremella products on the market mainly include dry products and canned products, and products are too single and its deep processing applications are weak. Crisp cookies are the main products of baked foods, with the feature of crisp taste, is popular as leisure food to consumers, has a huge market prospects for development. There are rare researches on the tremella crisp biscuit now, Therefore, in this research, the processing technology, quality characteristics, slow digestion characteristics, quality standards and the establishment of HACCP system was studied according to adding the tremella powder to the production of crisp biscuit, and the purpose was to produce a kind of crisp biscuit withslow digestion characteristics. The main contents and conclusions were as follow.1. The effect of different addition of tremella (0～40 g), corn starch (2～10 g), sugar (20～40 g) and baking temperature (160～200 ℃) on the texture, color and sensory qulity of tremella crisp biscuit were studied. Response surface method was adopted to optimize formula according tosensory score, got the best formula:low-gluten flour 100 g, butter 55 g, whole milk powder 7.5 g, tremella 29 g, sugar 30 g, corn starch 4 g, salt 1 g, egg 32 g, sodium bicarbonate 0.5 g, water 10 g, and baking temperature was 170 ℃. Tremella crisp biscuit producing by this formula and technology, had the pleasant tremella aroma, and itscolour and taste were boths good enough.2. The quality of tremella crisp biscuit produced by optimal formula and commercially available crisp cookies were compared, the results showed that the protein (7.83%), polysaccharide (3.87%), and dietary fiber (0.75%) of tremella crisp biscuit were higher than commercially available crisp cookies, while its fat and total sugar content were lower. There were no significant differences of the hardness and chewiness between different cookies, fragility of tremella crisp biscuit was significantly higher than others’. Tremella crisp biscuit accord with the requirement of GB/T 20980-2007 "national standard biscuit", its sensory score is match to commercially available tremella cookies, and significantly higher than control biscuit and ordinary crisp biscuit. The results showed tremella crisp biscuit was a kind of products with low calories and high nutritional value, having good texture and sensory quality, and the potential development is big.3. The effect of different tremella addtion (0-40 g) on starch digestibility and GI value for biscuit were explored, the results showedthat the SDS content of biscuits was increased with tremella addtion increasing, while GI value was decreased; the content of SDS in tremella crisp biscuit with optimum fomurla (29 g tremella) was 32.89% higher than that of control group, the GI value decreased to 67.636 at the same time, which is belong to moderate glycemic index food. It may because that the tremella is rich in polysaccharide and dietary fiber, which could affect the structure of the starch or its enzymatic hydrolysis reaction mechanism, etc. So the SDS content of biscuits was improved, the digestion rate and GI index were reduced as well. Thus, tremella crisp biscuit is a functional biscuits that are suitable for wider applicable people because of higher polysaccharide content and lower GI value.4. Through accelerated test, the acid value and peroxide value were adopted as the index to predict the shelf-life of tremella crisp biscuit. According to oil rancidity kinetic model, the shelf-life of tremella crisp biscuit stored at 37,47 and 57℃ were 176,95 and 61 d, respectively; according to the lipid oxidation kinetic model, that were 181,99 and 68 d, respectively. Based on the acid value and peroxide value, the dynamics model between temperature-shelf life were In (T)=-0.0036S+4.2344 (R2= 0.9714) and In (T)=-0.0036S+4.2538 (R2= 0.9622), respectively. Moreover, the relative error between forecast value and actual value is small, suggested it could well predict the shelf-life of products under different temperatures.5. The other properties of tremella crisp cookies were detected and analyzed further, the results showed that the tremella crisp biscuit contained the moisture 2.85%, acid value 2.82%, peroxide value 0.15 g/100g and the bacteria, pathogenic bacteria or other microorganisms indexes all accorded with GB 7100-2015 "food safety national standards of biscuits". On this basis, the enterprise product quality standards for tremella crisp biscuits was made, and set up the relevant HACCP system, could provide theoretical basis for the industrialization production of tremella crisp biscuits.