Development And Quality Analysis Of The Low Sugar Compound Jam With Hawthorn And Jujube

In this dissertation I developed healthier jam with fresh taste,unique flavor,high nutrition,and wide application ranged new type of low sugar compound.Fresh hawthorn and dried red dates as the main ingredients used in raw form.During the preparation process of jam pre-cooked fresh hawthorn fruit and dried jujube are used to make the jam to prevent browning and nutritional loss reduction;During the experiment,the type and amount of the thickeners were deter mined according to the gel strength value,water activity value and rheological properties of the jam,the optimal formula of the low-sugar jam was deter mined based on single factor and orthogonal optimization experiments.Design process optimization experiments to determine the best sugar addition and concentration time of jams.Finally,the shelf-life and composition of low sugar hawthorn-jujube compound jams were studied.At the same time,compared with the commercial hawthorn jams,the difference of the two jams and the quality advantage of low-sugar jam were found.The main contents of the study are as follows:1.Single factor experiment and orthogonal optimization experiment were designed to investigate the time,temperature and citric acid addition in pre-cooking solution.According to?L,?E as the evaluation index,it is the color difference meter results indicated to differentiate between precooked and non-precooked jam colors.The precooked hawthorn conditions are: precooking temperature is 95 ?,precooking time is 20 min,citric acid added amount is 0.6 %,under this condition,the value of ?L was 20.11 and the value of?E was 26.50.2.Jujube is carried out in two ways of softening which are boiling and steaming.It is based on the nutrient composition of red jujube pulp to deter mine the best softening conditions,and the nutrients are sugar and polyphenols.At the end steaming and softening duration was about 10 minutes.Under this condition,the total sugar contents in red jujube pulp were 30.4 %,and the total polyphenol contents were 2.74 mg/g.3.For thickening agent screening experiment done,four food gums,konjacgum,xanthan gum,sodium alginate,and guar gum were selected and added to the jam.Weigh 300 g hawthorn and jujube mixture slurry.The results showed that thickening agents influences on the gel strength,water activity value and rheological properties.Considering the influence of the glue on the gel strength value,the water activity value and rheological properties of the jam.The final result was a ratio of xanthan gum to guar gum was 3:7.Theconcentration of the compound thickener was at 0.8 %,the gel strength value of the jam was 15.111 g,the Aw value was 0.710,the consistency coefficient value was 35.156pa/s,and the area of the hysteresis loop is 2166.0 pa/s.In this state,the viscosity of the jam was appropriate,and the structure was destroyed by external force which is good resilience.4.The single factor and orthogonal optimization experiments were designed to deter mine the optimum formula of the jam.The gel strength value,total sugar content,and sensory score were used as evaluation indicators.The optimum formulation of the jam was deter mined to be at the ratio of hawthorn and jujube added was 7:3,the amount of sugar added was 20 %,and the amount of citric acid added was 0.2 %.According to this concentration sensory evaluation scored to jam on 93 points.5.To take 300 g of jam,and it is carried out at atmospheric boiling.According to the soluble solid content,color difference value and sensory evaluation index,it is deter mined that the jam plus sugar way is carried out by adding the sugar liquid with a concentration of 60 % in batches.The concentrated time was 35 min.At this time,the jam color was bright and the uniform structureed.The soluble solids content was 25.3 %,the ?E value was 78.9,and the sensory score was 85 points.6.To compare the basic physicochemical indexes,nutrient composition and rheological properties of low-sugar hawthorn-jujube compound jam and commercial hawthorn jam.We found that the content of protein,fat,vitamin C,etc.in the low sugar hawthorn-jujube compound jam was high.The commercial jam sauces have more apparently solids,higher hardness,and poor recovery after force.The specific experimental data is: low sugar jam total sugar content 30.8 %,ash is divided into 0.13 %,solids content is 25.5 %,moisture content is 76.3%.total flavonoid content is 1.1 mg/g,Vc content is 4.32 mg/100 g,total polyphenol content is 2.25 mg/g;the total sugar content of the commercial hawthorn jam is63.2 %,the ash is 0.12 %,the solids content is 55.7 %,moisture content is 70.2%.the total flavonoid content is 0.62 mg/g,and the Vc content is 2.03 mg/100 g.the total polyphenol content is 0.7 mg/g.7.The jam was sealed and stored at room temperature with cool and dry in a 100-mL glass bottle.The total colony number and nutrients content of the jam were deter mined during the storage process.When low-sugar jam is stored for 8 months,at this point,the total polyphenol value was 1.167 mg/g,and the Vc content was 2.23 mg/100 g.The total number of colonies in the jam was 800 CFU/g,which was in accordance with GB/22474-2008<1500 CFU/g.At this time,the low-sugar jam is still not spoilage.