Studies On The Technology Of Processing Kiwifruit Crisp By Expllosion Puffing Drying And Its Quality

With Kiwifruit deliciosa A. the main raw material, this dissertation is mainly on research of crisp, fragrant and sweet kiwifruit by utilizing one of new technology of food industry-low temperature pneumatic-puffing drying technology. This paper comprises three parts: the first part studies on kiwifruit slice technological process with non-sulfites as inhibitors. The second part acquired optimum parameters by single factor experiment then determine the fit parameters through quadratic cross rotary design method and carry through season analysis under the fit parameters. The third part is mainly on the nutrition and product's quality standard. Conclusions can be summarized as follows:1. The optimum inhibiting compounding of kiwifruit crisp with non-sulfites were 0.15% ZnCl₂, 0.10% Vc, 0.35%C₆H₈O₇.H₂O, 0.30% CaCl₂.2. After pre-experiment about desiccation curve and speed, the pre-drying were drying at 60℃.3. The thesis discussed the technology for abtaining the best puffed kiwifruit , analyzed the effect of rigidity of staple, thickness, moisture content, puffing temperature, residence time, vacuum temperature, vacuum time, moisture equilibrium time as well as pressure difference on puffed kiwifruit's qualities. The results: rigidity of staple 9.37 kg/cm²-18.39 kg/cm², thickness about 6 mm, moisture content 30%, puffed temperature 80℃, residence time 5 min, vacuum temperature 55℃-60℃, vacuum time 180 min, moisture equilibrium time 2 days, pressure difference 0.13 MPa.4. In the experiment rehydration rate has positive relation to puffing degree, the greater the puff degree, the more porous the product, and the more readily the water is picked up when rehydration.5. The effects of moisture content before puffing (X₁) , puffing temperature (X₂) , and vacuum drying time (X₃) on puffing degree (Y₁) , product's moisture content (Y₂) , Vc losing ratio (Y₃) , hardness (Y₄), crisp degree (Y₅) were significant. Regression equations from data analysis through quadratic orthogonal circumvolving combination eaperimental designs of three factors were found out (R²>0.85) :Y₁=1.57569-0.18252X₁-0.02167X₂+0.022865X₃-0.47721X₁²-0.23502X₂²-0.16431X₃²+0.02750X₁X₂+0.00250X₁X₃+0.01000X₂X₃ Y₂=6.93034-1.77831X₁-0.22849X₂-2.40579X3+0.51510X₁²-0.20792X₂²+1.36539X₃²-0.00250X₁X2-0.19000X₁ X₃+0.15750X₂X₃ Y₃=30.70026-0.7973X₁+2.63076X₂+4.99511X₃+0.28458X₁²+1.26215X₂²+1.25508X₃²+1.63750X₁X₂-1.75500X₁X₃+0.50500X₂X₃ Y₄=1100.00777+417.44585X₁+184.45830X₂+375.31158X3-68.56711X₁²-66.51650X₂²-172.59842X₃²+192.92500X₁X₂+305.62000X₁X₃+45.76250X₂X₃ Y₅=163.55168+35.26170X₁+11.00550X₂+27.10731X₃-18.83459X₁²-4.76317X₂²-17.91535X₃²+1.34000X₁X₂-9.94500X₁X₃+5.75250X₂X₃Optimizing Y₁,Y2,Y3,Y4,Y5 through data processing software, limiting Y₁> 1.2,Y₂ <7%,Y₃<35%,1000g4<1500g,Y₅> 150. The optimum code value is X₁=0.19 (31%),X₂=0.05 (80),X₃=0 (3), Y₁= (1.59),Y₂= (3.3),Y₃= (22.8),Y₄= (1415.42),Y₅= (198).6. The season experiment concludes that: the chroma of sweet chrysanthemum sugar 0.15%, vacuum degree 0.09MPa, time 20min which is the most favorite than cane sugar and malt dust.7. There retains most of the nutrition in the kiwifruit, because the process of explosion puffing drying is low-temperature and short-time. Compared with hot air drying it can produce equably and alveolate structure which is propitious to body's digestion. In a word, the puffed kiwifruit crisp is healthy, natural, organic food.