Study On Semi-manufactures Preservation And Products Processing Technology Of Henon Bamboo Shoots Based On Compound Method

China has many varieties of bamboo resources,and abundant bamboo shoots.Bamboo shoots are fresh,delicious and nutritious,and have a long history of eating in our country.They have high nutritional value,with good medicinal value and health care.Henon bamboo shoots（Phyllostachys nigra（lodd.ex Lindl.）Munro var.henonis（Mitf.）Stapf et Rendle）,taste sweet,property cold,have rich in dietary fiber,vitamins and minerals,and can be used as Chinese medicine,with the effect of clearing away heat and eliminating phlegm and so on.The fresh henon bamboo shoots are harvest season concentration in summer or autumn.If the harvest is not timely or not handled properly,a large amount of resources will be wasted,so it is very important to preserve and process the fresh henon bamboo shoots after harvest.In this paper,the henon bamboo shoots were used as raw material,study on heat treatment and chemical preserved technology of henon bamboo shoot.The effect on the quality of fermented henon bamboo shoots by different lactic acid bacteria,optimization of drying process of bamboo shoots by microwave combined with hot air were studied.Comprehensive utilization of henon bamboo shoots were enabled,and more methods for preservation and processing of henon bamboo shoots were provided.（1）Study on the preserved process of semi-finished products of henon bamboo shoots by thermal-chemical compound method.Some problems such as browning,tissue aging and rotting may decrease the quality of henon bamboo shoots and even lost edible value during preservation,which will seriously affect the production,processing and sale.In this paper,the effects of heat treatment and sodium metabisulfite solution was studied on the sensory score and SO₂ residual quantity.The results showed that heat treatment and sodium metabisulfite solution could effectively maintain the quality of preserved henon bamboo shoots,and the addition of the sodium metabisulfite was the higher,the preserved effect was the better,and the best result was that both of them act simultaneously.Heat treatment and sodium metabisulfite solution could significantly improve the sensory score（P<0.05）,increase the brightness of the henon bamboo shoots,and make the hardness decrease slowly.The hardness of henon bamboo shoots in 11 groups（heat treatment+0.5% citric acid+0.20 % sodium pyrosulfite）and 12 groups（heat treatment+0.5 % citric acid+0.25 % sodium pyrosulfite）was significantly higher than that in other groups（P<0.05）at 64 days,but 11 groups lost food value.The turbidity of the 12 groups had no significant change and was significantly lower than that of the other groups（P<0.05）during preservation.The SO₂ residual quantity in 12 groups was（0.045 ±0.000）g/kg at 60 days,which met that sulfur dioxide residue should not exceed 0.05 g/kg in canned vegetables（bamboo shoots and pickles only）,according to the GB 2760 National Food Safety Standard for Uses of Food Additives.In order to obtain the good preserved quality and long preserved time of henon bamboo shoots,it was suggested that the fresh bamboo shoots should be soaked in 0.25 % sodium metabisulfite solution after 60 s of boiling water treatment,preservation period could be more than 60 days,and the SO₂ residual quantity should be safe and reliable.（2）Study on quality change of henon bamboo shoots by compound strain fermentation.In order to shorten the fermented cycle and improve product edible properties and safety,Leuconostoc mesenteroides,Lactobacillus zeaze and Lactococcus lactis or more strains were used for the fermentation of henon bamboo shoots,and compared with natural fermentation,the effect offer mentation of different lactic acid bacteria on the quality of henon bamboo shoots was studied.The results showed that the inoculated fermentation pH value was lower than the natural fermentation.Inoculation fermentation total acid was higher than the natural fermentation.The control effect of inoculated fermentation on nitrite content was better than natural fermentation.Inoculated fermentation nitrite content was obviously lower than the natural fermentation（P<0.05）at 5 d.The natural fermentation and mixed strain fermentation color was higher than pure strain fermentation.Lactic acid bacteria inoculated fermentation could increase the fermentation rate of henon bamboo shoots,reduce the nitrite content and improve product quality,while fermentation effect of combination of Lactobacillus zeaze and Lactococcus lactis was the best.（3）Study on drying process of henon bamboo shoots by microwave combined with hot air.In order to get dried bamboo shoots with less drying time and good drying quality,by central composite design coupled with response surface methodology,the effect of microwave drying power,time and hot air drying temperature on sensory score,total drying time,rehydration rate,color difference and hardness were examined on the basis of single factor.Optimum drying process conditions of bamboo shoots by microwave combined with hot air was determined.The results showed that the optimal drying process were as follows: microwave drying power,6.3?W/g;microwave drying time,60?s;hot air drying temperature,65?℃.Under these conditions,sensory score was 85.6,total drying time was 200 min,rehydration rate was 6.17,dry product color difference ΔE* was 19.99,rehydration product color difference ΔE* was 13.92,dry product hardness was 19511.23?g,rehydration product hardness was 20010.71?g and water content≤ 8 %,.The experiment proved that the model was reasonable and reliable,and the process will be of great significance to the development of bamboo shoot industry in the future.