Study On Screening Parameters And Evaluation Of Nutritional Value Of Solid-state Fermentation Process Of Tea Residue

This experiment used tea residue as raw material,optimized the tea residue fermentation process parameters by biological fermentation technology such as solid-state aerobic fermentation and silage fermentation in order to increase the nutritional value of tea residue and provide a theoretical basis for the feed of tea residue resources.This experiment was divided into two parts:Experiment 1:Nutritional improvement of tea residue by solid-state fermentation with Aspergillus niger.In this part,a solid-state fermentation using Aspergillus niger was conducted to improve the nutritional quality of tea residue.Considering the tea tannin and crude protein content as index,a single factor experiment design and a L₉（3⁴）orthogonal design were adopted to screen the optimal corn flour supplemental level,the ratio of substrate to moisture,inoculation,fermentation temperature and fermentation time.The results showed that:（1）added 5%corn flour,inoculated 1.00×10⁶ Aspergillus niger spore per gram fermentation materials,controlled the ratio of substrate to moisture 1︰1.4 at 37℃for 8 days could get the optimal result.（2）Under the optimal fermentation conditions,calculated based on dry matter and compared with the control group,the crude protein content was increased from31.22%to 44.56%（P<0.05）,the true protein content was increased from 23.64%to 36.99%（P<0.05）,crude fat content was increased from 4.06%to 5.13%（P<0.05）,Ash content was increased from 4.09%to 6.09%（P<0.05）,calcium content was increased from 0.75%to1.10%（P<0.05）,phosphorus content was increased from 0.32%to 0.47%（P<0.05）and the content of 17 kinds of amino acids increased from 18.45%to 23.38%（P<0.05）;the tea tannin content was decreased from 11.63%to 2.42%（P<0.05）,neutral detergent fiber content was decreased from 39.85%to 32.96%（P<0.05）and the acid detergent fiber content was decreased from 15.70%to 12.28%（P<0.05）.Our results suggest that the use of solid-state fermentation with Aspergillus niger can improve the nutritional value of tea residue significantly.Experiment 2:Effects of bran and lactic acid bacteria preparation on silage quality and nutritional value of tea residue.This part was conducted to investigate the effects of bran content and the concentration of lactic acid bacteria preparation on silage quality and nutritional value of tea residue.Four concentrations of lactic acid bacteria preparation（0,50,100 and 200 mg/kg）were added to five bran contents（0%,5%,10%,15%and 20%）raw materials.Silage quality and nutritional value were evaluated after 45 days.The results showed that:compared with tea residue silage alone,adding bran increased ammonia/total nitrogen and contents of lactic acid,acetic acid,dry matter,Ash significantly（P<0.05）,and reduced the pH,contents of crude protein,acid detergent fiber,and tea tannin of silage tea residue significantly（P<0.05）.Adding lactic acid bacteria preparation reduced the pH,ammonia/total nitrogen and contents of acetic acid,dry matter and acid detergent fiber significantly（P<0.05）,and increased the contents of lactic acid,crude protein,Ash and tea tannin of silage tea residue significantly（P<0.05）.The bran content,concentration of lactic acid bacteria preparation and interaction between the two all affected the pH,ammonia/total nitrogen,and contents of lactic acid,acetic acid,dry matter,crude protein,Ash,and acid detergent fiber of silage tea residue significantly（P<0.05）,bran content and the concentrations of lactic acid bacteria preparation affected tea tannin of silage tea residue significantly（P<0.05）,but the interaction between the two had no significant effect on content of tea tannin（P>0.05）.Considering the silage quality,adding 100 mg/kg of lactic acid bacteria preparation to the mixture of 85%tea residue+15%bran could obtain better quality silage tea residue feed.