Study On Method And Mechanism Of Decreasing Content Of Anti-nutritional Factor Phytic Acid In Brown Rice

Brown rice as traditional food and food resources, what contains multiplenutrients and functional ingredient. With the increasing scientific of diet conceptas well as food safety,nutrition and the strengthening on health care, people payhigh attention on nutrition health care of brown rice. But the brown rice contains acertain amount of anti-nutritional factor—phytic acid. The brown rice containsapproximately 0.89% of phytic acid. It is a cereal that contains higher phytic acid.Also it is the most nutrition defect of the brown rice. Phytic acid can chelate withCa,Zn,Fe and so on in food, then form insoluble composite which reducephysiological utilization of Ca,Zn,Fe and so on.;Phytic acid also can forminsoluble composite with protein. It reduces the utilization of amino acid;Phyticacid also restrains the activity of some digestive enzyme(such as protease,amylase,trypsin and so on ),consequently it influences the utilization of protein,starch,fatty. Phytic acid is an important reason for people whose staple food isplant food absent of Ca,Zn,Fe. The anti-nutritional factor is a big problem whaturgently has to be settled.Phytic acid not only results in the descending of multiple nutrients utilizationby organism. At the same time, It also increases phosphor content in excrement.Accordingly, it increases phosphor accumulation and then leads to theenvironment being severely polluted and destroyed.This paper takes the brown rice as research target, uses ultrasonic tostrengthen mass transfer and makes use of phytase to reduce anti-nutritionalfactor--content of phytic acid in brown rice. For the sake of improving thenutrition defect of brown rice, developing environment-friendly food and foodresources which is safe,high nutritious,low content of phytic acid and improvingnutrition quality of the traditional main-stream food .This paper mainly carries onthe following research:1 By making experiment of enveloped embryo , naked embryo andiodination-gas on brown rice, studied on brown rice grain's exogenous waterosmotic route and analyze the influence of grain structure to osmotic route;Bymeasuring phytic acid content and brown rice rate of brown rice sample, to studyphytic acid content aberrance of varieties of brown rice as well as the relationshipbetween phytic acid content and brown rice rate;By spewing a spot of KH2PO4outside the root in different rice growing period, to study the impact of phytic acidcontent to craftwork quality. Through these studies we can conclude as followings:(1) After dipping in phytic acid grain, the main approach of water enteringinto phytic acid grain is embryo->inner-cotyledon->albument.(2) The phytic acid content in brown rice differs according to variety,In eightbrown rice sample, the brown rice content range from 0.77% to 1.11%. Theaverage is 0.92%, standard deviation is 1.21, variation coefficient is 13.18%.(3) After the rice tasseled, to spew a small quantity of KH2PO4 appropriatelyis better to grain ripening. The aim is to increase phytic acid content. Formingphytic acid is in favor of synthesizing starch. Phytic acid can restrain amylase andaccelerate starch synthase transform starch, increase phytic acid content, improveintact rice rate, and reduce chalky area and chalky rate.(4) Phytic acid content in brown rice has certain impact on technics quality.Thereinto, it is directly proportional to brown rice rate,gaining rice rate and phyticacid content in brown rice and inversely proportional to broken rice rate.2 Studied on phytic acid measuring approach, and analyzed accurate degreeand precision degree,t-test and recoveries for the spiked sample test. Throughthese test we can conclude that:(1) When there is no phytic acid standard sample, we'd better to use methodsof phosphor colorimetry and scomplexometric titration thorium to measure phyticacid content. To measure minim phytic acid content in sample, colorimetry hasmany advantages such as little disturbing ingredient,stronger specialty,colorstability, accurate, quick, high delicate and so on.(2) The test results indicate that: the results of phosphor colorimetry is betterthan Orthophenanthroline colorimetry and scomplexometric titration thorium. It isquick, accurate and delicate. And it is close to high performance liquid chromato-graphy;T-test of phosphor colorimetry indicate that the result is up to the mustard;From the results of recoveries for the spiked sample test, the average recoveriesrate of phosphor colorimetry is between 99.66±1.0% and 100.28±1.5%, totalaverage recoveries rate is 100.08±2.0%. It shows high reliability.3 Analyzed the mechanism of ultrasonic strengthen mass transfer course. Bycontrast test, we studied the influence of ultrasonic on drink speed of brown ricegrain and ultrasonic field to enzyme reactions;By single-factor experiments, westudied ultrasonic power,frequency and the influence of time on enzymereactions;At the same time, by using L9(33)orthogonal experiment to optimizeultrasonic condition. The studies above conclude that:(1) Ultrasonic has the function of strengthen mass transfer course. It canincrease permeation speed of water in brown rice . In ultrasonic field, after brownrice grain dipping 20min, its water contents increase from 14.8% to 21.8%, addedabout 47%. It is 20 times more than the moisture adding quantity (adding from14.8% to 15.1%) of brown rice grain what has not ever suffered ultrasonic sound.(2) Ultrasonic sound frequency has effect on the reaction course of phytasehydrolyze phytic acid. When the frequency is between 24~32kHz, phytase energyis in a relatively steady high activity state. Ultrasonic impacts on chemical reaction.Its mechanism is not only relevant to molecule's reciprocity, but also to ultrasonicsound cavitation.(3) Ultrasonic power has deep influence on enzyme activity. This researchindicates that when P<4w, along with power increasing, phytase activity increasescontinuously;when p is between 4~6w, phytase energy is in a high activity state.When P>6w, phytase activity decreases continuously until in an inactivate state.From this result, by properly dealing with proper intension we can improvephytase activity and advance enzyme reaction.(4) Ultrasonic sound time has effect on the reaction course of phytasehydrolyze phytic acid. When ultrasonic effect goes on about 20min,xenobiotics—phytase has basically completely filtered into the aleurone layer. So the properultrasonic effect time is 20~30min.(5) Dealing with proper strength ultrasonic, it would boost up cellmembrane's osmosis and promote enzyme catalyse activity. The results indicatethat the ultrasonic optimizing condition is: the ultrasonic power is 5w, ultrasonicfrequency is 28kHz and time is 25min.(6) In biochemical reaction processing, cavitation effect is very important.Cavitation effect can efficiently promote reversible reaction, reinforce substancetransportation inside and outside of the cell, enhance microbial activity, reduce therestrain effect of hypo-metabolizing production accumulation to microbe metabo-lize, promote synthesizing metabolite;The micro-streaming caused by ultrasoniceffect impacts on producing substrate and enzyme molecule. It increases thecontact times of the two and then increases the reaction velocity. The productionwould release quicker in this micro-streaming effect and accelerate biochemicalreaction velocity.4 Studied on phytase effect mechanism and dynamics, and determinedingredients on product of phytic acid in brown rice;By single-factor experimentswe studied the influence of temperature,pH and substrate concentration(liquid-to-material ratio) to enzyme reaction;At the same time, we adopted CentralComposite Orthogonal Design and response surface analyze to optimizeenzymolysis condition. Through the studies above we can conclude that:(1) Substrate concentration (liquid-to-material ratio) has double influence thatis activation and restrain on enzyme reaction velocity. When liquid-to-materialratio>10:1, the change rate of organic phosphor increases by substrateconcentration. The velocity of enzyme reaction is in a direct ratio of substrateconcentration. Substrate concentration has activation has activation effect onvelocity of enzyme reaction. When liquid-to-material ratio <10:1, reaction velocitywould descend along with concentration increasing. The most important reasonpossibly is the descending of substrate concentration and the restrain of productionto enzyme.(2) Temperature is one of the important enzyme reaction factors. In ultrasonicsound field, the most proper temperature of phytase is 50℃.(3) The liquor pH value has influence on enzyme reaction. In ultrasonicsound field, the most proper pH of phytase is 6.0.(4) The water activity has influence on phytase reaction. The phytasehydrolysis reaction is not only relevant to water content in the system, but alsorelevant to the water utilization in the system. Water activity directly impacts onthe hydrolysis results. When the Aw <0.8, the phytase activity will be restrained;When Aw value drop to below 0.50, phytase will be restrained strongly and loseactivity. When Aw value above 0.9, it can promote the enzyme reaction. In enzymereaction, besides substrate effect, water as transportation medium can promoteenzyme and substrate activation by hydrating.(5) Adopting Central Composite Orthogonal Design and response surfaceanalyze, the best condition of optimized enzymolysis reaction is: pH6,T50℃,liquid-to-material ratio=10:1.(6) In the condition of the test , the major ingredients of product are IP2 andIP2.5 Decrease the water content of brown rice below security water (15%) bydryness, then measure and compare the properties of structure mechanics andgelatinization of brown rice in enzymolysis fore-and-aft and polished rice. Andpreliminarily analyze the affect of the dryness course and enzymolysis reaction onthe structure mechanics characteristics,gelatinization characteristics,organicphosphor content and protein content. The results showed:(1) When the sirocco temperature is 35℃ and the dryness time is 135min,the rate of grain stress crack is 1.5%. When the temperature is 65℃ and thedryness time is 70min, the rate of grain stress crack is 15%. We choose the drynesstemperature is under 35℃, then decrease the water below 14.5% slowly.(2) After the brown rice goes through enzymolysis reaction, its compressivestrength, flexural strength, and shearing strength all decrease about 20%. But theyare all a little higher than polished rice. So the resisting burst strength of the brownrice after enzymolysis satisfies requestion of the polished rice.(3) The gelatinization temperature (64℃) of the brown rice after enzymolysisis distinctly lower than the brown rice unenzymolysis (71℃), and a little higherthan head rice (61℃). Its top viscidity value,viscidity dilapidation value andgelation value are all improved.(4) The dryness course has no influence on organic phosphor content in thebrown rice sample;Enzymolysis reaction basically has no influence on proteincontent of the brown rice.In a word: Using phytase to reduce phytic acid content in brown rice couldefficiently make use of brown rice nutritious,improve nutritious defect, developsafe,nutritious,hygienical environment-friendly food and provide a scientifictheory and probe an important approach. The harmony between nature and peopleis the motivity of anything prosperity. Reducing phytic acid content in brown riceis very important to repair and protect the environment where people survive. Ifthis production perfect further and then dive into practice, it has good socialbenefit,economic benefit and environmental benefit, as well as high scientificvalue.This paper in many ways only does primary search. And it needs to do furtherresearch then make it improvement.