The Development Of Persimmon Compound Jam

The development of two kind of persimmon jams was studied in this paper,with persimmon,hawthorn and lemon as the raw materials.The orthogonal experiment was used to determine the optimum processing conditions which included the ingredients ratio,stewing time and the color-protecting reagent of persimmon-hawthorn jam.Additionally,the response surface methodology was used to optimize the persimmon-lemon jam.After being stored at 37?for 60 days,the quality indexes including microbiological,sensory,and chemical fluctuations of the end-product were examined.The main results were as follows:(1)The optimization process of persimmon-hawthorn jamThe optimized process conditions were achieved by using single factor test and orthogonal experiment,as stated in the downmentioned results.The ratio of persimmon pulp to hawthorn pulp was 4:1 and the ratio of mixed pulp(persimmon pulp and hawthorn pulp)to water was 2:1,the sugar content was 20%(w/w),and the boiling time was 10 min.Based on the orthogonal test of the color difference,the optimum addition of D-isoascorbate,tea polyphenols,and EDTA disodium,was 0.28%,0.022‰,and 0.014‰(w/w),respectively.Besides,0.10%of?-carotene was chosed as a toner for the jam.(2)The optimization process of persimmon-lemon jamThe optimized conditions of persimmon-lemon jam were determined by the response surface methodology.It was found that the ratio of persimmon pulp to lemon juice was 7:1,the addition of citric acid and sugar was 0.20%and 20%(w/w),separately,and the boiling time was 6 min.Meanwhile,the concentration of?-carotene,as the toner was determined to be 0.10%.The color indexes of the produced jam included L*,a*,and b*were 54.64,9.44,and 13.14,respectively.(3)The storage stability of the two jamsThe persimmon-hawthorn jam and persimmon-lemon jam were sterilized and incubated at 37?for 60 days.The results showed that the sensory score decreased during the storage period(from 86 to 71),but it still could be accepted.The titratable acidity and soluble solids was relatively stable;conversely,Total phenolic content was gradually decreased(from 14.3 to7.9 mg/g).The total bacteria count were increased significantly(from 19 to 453 CFU/g),but it was still far below the national standard recommendtion(10~4 CFU/g).For persimmon-lemon jam,the sensory score declined during the storage period(from 92 to 61),but it could be accepted within 40 d(71).The content of titratable acidity,total sugar,and soluble solids was stable during the storage period,But the Vc was decreased significantly(from 30.5 to 10.5 mg/100g).However,the total bacteria increased(from 22 to 603 CFU/g),but it was in the margin of safe of the national standard recommendation(10~4 CFU/g).Eventually,the shelf life of persimmon-hawthorn jam was estimated about one year,while it might be half a year for the persimmon-lemon jam.