Preparation Of Porphyra Haitanensis Condiment From Solid-state Fermentation

Porphyra haitanensis, a traditional warm-water aquaculture algae, is endemic to China, which have enormous bioactive functions such as decreasing the blood pressure, blood fat and blood sugar, immune regulation, anti-tumor, improving the intestinal flora and intestinal micro-environment, etc. Porphyra haitanensis is mainly cultured in Fujian and Zhejiang Pronvince. The cultivation area has more than one hundred thousand acres in Fujian province. Due to its special biological functions, it has a great development prospect.In this paper, Porphyra haitanensis was fermented by Aspergillus oryzae. Salt, monosodium glutamate and sugar were added to the liquid extracted from the fermented, then the mixture was spray dried to obtained a new type of fermented seasoning powder. The main research content is as follows:1. To investigate of koji making conditions, protease activity was determined as an evaluation index. After the response surface optimization, The regression equation was achieved as follow: Y=-25062.29613+246.97239X1+711.40925X2+580.36760X3-3.91313XiXi+0.126 35X1X3+3.97792X2X3-2.05052X12-53.69072X22-5.04317X32 The effects of the investigated factors on protease activity was ordered as follow: Water content (X1)> sugar content (X2)> fermentation time (X3). The optimal condition for koji making was:0.5‰ (based on dry Porphyra haitanensis meter) of Aspergillus oryzae GLS inoculation,7% of (based on dry Porphyra haitanensis) sucrose,55% of water, and 60 h fermenting time under 32℃.2. To investigate the ideal fermentation condition of the Porphyra haitanensis, the amino nitrogen content, protein content, crude polysaccharide content were determined as evaluation indexes, and orthogonal experiment was carried out. The effects of the investigated factors on these evaluation indexes was ordered as follow:Brine concentration> fermentation time> solid-liquid ratio. The best fermentation conditions was:1:8 of the solid-liquid ratio,28 d of fermentation time, and 12% of brine concentration, under these fermentation conditions, Amino nitrogen content in fermented liquid is 3.622 g/100g, dissolubility protein 21.05 g/100 g, coarse polysaccharide dissolution quantity is 21.16 g/100 g.3. Fermentation effect validation. After 5 d fermentation, Porphyra haitanensis protein dissolution rate achieved to 16.07%, and polysaccharide dissolution rate achieved to 18.27%. Compared with unleavened dissolution, protein dissolution quantity increased by 168.42%, and crude polysaccharide dissolution quantity increased by 14.86%.4. By orthogonal experiment, the factors influence on the flavor of fermented liquid of Porphyra haitanensis could be concluded and ordered as follow:salt> MSG> sucrose, The optimal arrangement scheme was:1.5% of salt,1.5% of sugar, and 2% of monosodium glutamate.5. The best choice of spray drying agent was 1% CMC for preparation of the Porphyra haitanensis condiment. Under this condition, flour yield was 56.45%, moisture content was 4.21%, bulk density was of 0.455g·cm-3, and dissolution was of 84s/g, protein content was 13.87 g/100 g. Powder was milk-white, soluble and delicate, with a distinctive salty taste.