Research On The Quality Characteristics And Functional Effects Of Chewable Tablets Of Lactic Acid Fermented Pyracantha Fortuneana Fruit

Pyracantha fortuneana fruit（PFF）,as a new food resource fruit,has extremely high edible and medicinal value due to its rich nutritional ingredients and natural active ingredients.However,its usage is hindered by the disadvantages including small fruitsize,rough and sour taste,indirect consumption,the seasonal and difficult storage of fresh fruit,etc.Lactic acid fermentation（LAF）is an important food production and preservation method.Fermentation can produce acid to extend the shelf life of food,form a unique flavor,and change the texture and nutritional characteristics of food.Drying is a more traditional processing technology that extends the food storage period and effectively retains the quality of the fruit.At present,the research on the quality of fruits and vegetables by drying technology is mainly focused on the original fresh materials.In addition,there are relatively few researches regarding the drying methods of fermented materials and their effects on edible quality.For this reason,this study mainly explores the effects of fermentation and drying processes on the taste quality,nutritional functional quality,flavor quality,and physical and chemical properties of fresh PFF.Thus,this research may be able to provide relevant guidance and suggestions for regulating the edibility,safety and functionality,processing technology,development and design,and shelf life prediction of PFF products.The main research contents and results are as follows:（1）The research analyzed the basic nutritional components,taste quality and functional characteristics of PFF,and studied the processing parameters of LAF to prepare its optimal fermentation broth.The results showed that the fresh PFF is not only rich in dietary fiber（17.80%）and minerals,but also is rich in organic acids,of which malic acid,citric acid and succinic acid have the highest content.Several experiments are conducted,which includes the fermentation with Lactobacillus bulgaricus,the three-factor&three-level experiment,response surface optimization experiment and verification experiment of LAF.Analysis showed that the optimal response value of PFF fermentation（total acid:total free amino acid:sensory evaluation=0.4:0.3:0.3）is influenced by fermentation time>liquid-to-material ratio>inoculation amount.Additionally,the interaction of the two factors is strong.At the same time,the model has a stable point in the test range.The optimized LAF parameters for PFF berry pulp are:inoculation amount 2.1%,liquid material ratio 2:1（m L/g）,fermentation time 96 h.The PFF pulp prepared under this condition has a smaller particle size and lower polyphenols damage than other experimental groups and fresh fruits.The content of total acid,total soluble sugar,free amino acid and soluble dietary fiber is also higher in the optimized group.At the same time,compared with the fresh fruit,the fermentation broth can add lactic acid,acetic acid and other flavor components.The total amount of organic acid is also increased significantly from26.43 mg/g dry basis of fresh PFF to 40.75 mg/g dry basis of the optimal PFF fermentation broth.The aforementioned reslutls indicate that appropriate LAF conditions can enable the fermentation broth to have a higher retention rate of nutrients and a better rate of improvement in sour and rough taste.（2）The effects of five different temperatures and four drying methods（Hot Air Drying,HAD.,Vacuum Freeze Drying,VFD.,Hot Air-Microwave-Assisted Vacuum Drying,HAMAVD and Hot Air-Assisted Microwave Drying,HAAMD）on the quality of the optimal hyracantha fermentation broth of PFF were studied.The research results showed that at 70℃HAD temperature,the amount of water for pyracantha fruit powder is less,the retention rate of color,5-hydroxymethyl furfural and functional components are higher,and the energy consumption is also slightly higher.When it is dried with microwave combining technologies,the HAMAVD and HAAMD processes are not only effective in reducing energy consumption,but also result in products that are better in terms of color,rehydration,fluidity,tissue structure,taste quality,nutritional properties and aroma substances.In addition,HAAMD minimizes time and energy consumption,which may be due to the use of high temperature（microwave drying）followed by a gradient low temperature dehydration method.Furthermore,the fluidity,porosity,rehydration,umami quality and functional ingredient retention rate of HAAMD fruit powder are not as good as VFD.In terms of water/oil retention,nutrient ingredient retention rate,taste quality and aroma characteristics of volatile ingredients,the difference between the above two is not significant.However,HAAMD fruit powder has better dispersibility,more uniform particle size,smaller color change rate,less moisture absorption,and easier transportation and storage.In summary,the orderly cooling program combined with microwave drying technology can not only improve the quality of dried products to a certain extent,but also has lower energy consumption rate and lower time cost.Thus,it is suggested that considerations should be given to the use of hot air combined with microwave drying technology for the fermentation of PFF to perform dehydration and drying treatment.（3）The research also explored and evaluated the design,safety,edibility,function and shelf life of PFF chewable tablets.The results showed that the optimally fermented and dried PFF chewable tablets have a net fruit powder content of 50%,a maltodextrin addition of 20%,and a sugar alcohol addition of 30%（the mass ratio of xylitol to mannitol is 3:2）.When the sweetness is 30%（6%sweetness comes from PFF powder）,the designed product has high hardness,crispness,consumer satisfaction and sensory score of fuzzy comprehensive evaluation.At the same time,the product’s moisture content,color,nitrite content,total number of colonies,total number of yeasts and molds,and E.coli all meet the product production standards.Besides,the cyanogenic glycosides that may be present in the fresh fruit are also removed by the processing.In addition,its rich dietary fiber and other nutrients,unique flavor and soft sweet-sour ratio（15:1）have obtained high edible quality evaluation.Further analysis of the sample’s ability to adsorb glucose,inhibit starch hydrolysis,and adsorb nitrite（NO₂^-）and cholesterol in simulated in vitro metabolism was also implemented.Results showed that its adsorption capacity for glucose is about 18.50 mg/g,and the starch digestion inhibition rate is12.20%.The minimum glycemic index can be also reduced by 46.59.The maximum NO₂^-adsorption capacity is 6.55 ug/g（p H 2.0）,while the maximum cholesterol adsorption capacity is 31.23 mg/g（intestinal environment）.The results further indicate that the sample with rich porous dietary fiber has a certain degree of hypoglycemia and the function of lowering blood fat.Finally,the shelf life prediction through high temperature accelerated deterioration experiments showed that when the taste quality,color and microbiological safety indicators of the PFF chewable tablets are all qualified,it is determined that the storage environment at 35℃and 45℃should not be stored for more than 76days and 36 days respectively.When the solid shelf life ratio Q₁₀ is 2.11,the Pyracantha fortuneana fruit chewable tablet can be stored for 161 days at 25℃and 769 days at 4℃.This result indicated that its storage in a fresh-keeping refrigerator is not only beneficial to flavor,taste and nutritional quality,but also to improving the safety and storage period.