Study On Pepper(Piper Nigrum L.) Decortication Technique And Mechanisms By Solid State Fermentation

Pepper(Piper nigrum L.) is known as "black gold", said the king of spices, and versatile. Currently white pepper processing methods are mainly traditional natural impregnation method, but this method produced poor quality pepper. Solid state fermentation conducted for pepper peeling, fermentation time is short, less water consumption, the resulting white pepper odor, high-quality. But the most effective solid-state fermentation peeling technology is not matur, and still in the stage of laboratory scale, and peeling mechanism has not been elucidated.Firstly,the study take pepper fruit as the research object, with the decrustation rate, decrustation time, value of chromatism of the product and product reproducibility as index pepper in solid-state fermentation decortication, and room-temperature water, hot water action as a basis, combined with additives acid, alkali, salt, chelating agents, surfactants and so on chemicals soaked pepper fruit as pretreatment on solid-state fermentation, committed to finding cost-effective pretreatment.Conclusions are as follows:(1) Hot water treatment effect than room temperature water for peeling pepper is better; room temperature water for peeling rate is about65percent overall, while the hot water is generally95%(2) Adding the soaking liquid acid and ethephon are better for peeling pepper; hot water with acid and ethylene to make pepper color value increased to about55, peeling rate is almost100%, Ethephon also significantly improved fermentation stability, high product repeatability.(3) Using hot water, a combination of acid and ethephon treatment works best for peeling pepper:after that pepper fruit pH3.0citric acid solution by soaking50℃20min, soaked in15.0mL/L ethephon solution in1-2h treatment, then solid-state fermentation, the fermentation process is stable, peeling rate of100%, the resulting white pepper no odor, color values L to56.39, and consistent with the whiteness of white pepper commercially.(4) Handling (3) resulting product quality analysis and found that the main chemical ingredient products piperine as4.97g/100g, non-volatile ether extract content7.762g/100g, higher than the commercially available white pepper, and ethephon volume<1mg/kg, meet the requirements. Sniffing the odor, the off-odor of four components detected by gas chromatography and found to contain n-butyric acid4.21μg/g, is obtained0.42%of white pepper dipping natural content. The other three components contain no odor.Secondly, we sampled at five time points during the solid-state fermentation, for activity, and the results show that the whole pepper in solid-state fermentation process, polygalacturonase highest activity in the fermentation48h of1785.67U/mL; pectinesterase inmaximum enzyme activity1445.62U/mL at36h; cellulase activity has a maximum at48h1330.17U/mL; minimal xylanase activity,60h when the maximum535.17U/mL; undetected pectinlyase activity.Then using high purity enzymes, including pectinase P2736and pectinase P4716(both main component of pectinlyase, polygalacturonase, pectinesterase, and a small amount of hemicellulase and cellulase), pectinase Y-23(the main component of pectinlyase), cellulase, xylanase, alone and in combination peeling test results were as follows:(5) With increasing concentration of three pectinase peeling rate and pepper color value increases; the enzyme concentration was4-6g/100g when, in solid-state fermentation12h peeling rate can reach85%, the color value of about51.0, and with the increasing concentration of both essentially no change at24h pepper peeling100%. Cellulase enzyme solution and the concentration of the solution to the peeling effect xylan pepper little effect.(6) Using a simple enzyme soaking pepper12h,5g/100g pectinase P2736and P4716,0.1g/100g pectinase Y-23solution of pepper peeling rate of about85%, while the xylanase and cellulase peeling rate was less than10%; using a single enzyme soaking pepper24h, pectinase P2736, pectinase P4716, pectinase Y-23was peeling rate of up to100%, while the xylanase and fiber peeling rate luciferase was almost no change.(7) Mixed enzyme treatment peeling slightly better than a single enzyme treatment.Finally, the changes in the study of solid state fermentation before and after the discovery of the chemical composition of the epidermis pepper, freshly ground pepper pericarp fat waxy, water-soluble substance, pectin, hemicellulose, lignin and cellulose were6.18%,30.33%,8.72%,23.93%,28.05%and2.24%. In pepper rapid biological peeling, the highest removal rate of pectin, up58.4percent; lignin, followed by7.17%; fat waxy lowest, only1.94%.Scanning electron microscopy with structural changes before and after fermentation pepper, freshly ground pepper found in a layer of waxy skin, accumulation of the spotty distribution, pepper slice cell layer honeycomb; fermented pepper skin covered with mycelium and spores, pepper facets honeycomb disappears, it becomes flat, the basic structure of the plant cell destruction.These results together indicate that:solid fermentation plays a major role in enzyme pectinase polygalacturonic acid and pectin lyase enzyme, followed by fiber luciferase, a small amount of xylanase work.