Study On Processing And Technology Of Cloudy Blueberry Juice

This paper mainly studied processing technologies of cloudy blueberry jucie. Cloudy blueberry juice of better quality were produced by reducing astringency, improving color stability and ehancing suspension stability.Gelatin and PVP were applied to remove tannin in blueberry juice.Orthogonal experiment results showed that the optimal condition for gelatin to adsorb tannin was: adsorption temperature 30℃, adsorption time 30mins,the dosage of 1% gelatin solution 10mL/100mL,the rate of tannin's removal was 65.60%.The optimal condition for PVP to adsorb was: adsorption temperature 30℃,adsorption time 25mins, the dosage of PVP 5g/L,the rate of tannin's removal was 74.48%. Embedding experiment showed that when the dosage ofβ-cyclodextrin is 0.30%,the rate of tannin's removal was more than 80%. The astringency shielding experiment showed that,at the same conditions, the jucie adding 1.0% trehalose tastes better and the astringency was lighter. Trehalose also can protect the color of juice.Citric acid can inhibit the anthocyanins degradation and can enhance the color stability of blueberry juice during one week storage. The color stability of blueberry juice was better at dosage of citric acid 0.15%.Effects of co-pigments on the color stability of blueberry juice during one week storage were studyed. The effect of tea PolyPHenols was best, sodium sulfite didn't work. The effect of Pentasodium tripolypHospHate and L-Cysteine were steady. The effect of L-lysine declined with dosage increasing.Studyed the stability of blueberry juice, adding different levels of CMC-Na, sodium alginate, pectin, carrageenan and agar.The results showed that juice adding CMC-Na, sodium alginate, had good stability. When the ratio of CMC-Na, sodium alginate, pectin was 1:2:1, with 0.10% adding, the stability of blueberry juice was better. And the stability of blueberry juice was optimal when it was homogenized twice at 20 MPa.The optimum technological parameters of cloudy blueberry juice were determined thro- ugh orthogonal experiments and methods of sensory evaluation.The result showed that infl- uencing degree of factors was as follows: the dosage of original blueberry jucie>the dosage of citric acid>the dosage of stabilizer > the dosage of trehalose. The best formula was: the do- sage of original blueberry jucie 50%, the dosage of citric acid 0.10%,the dosage of stabilizer 0.12%, the dosage of trehalose 0.5%.The result of storing experiments illustrated that: the stability and color of blueberry cloudy juice kept well in 60 days under 4℃: high temperature 37℃maked the quality of blueberry cloudy juice lose quickly.