Study On The Regulation Of Meat Pork Protein Oxidation By Microcapsulated Mulberry Polyphenols

The realization of oxidation regulation in the processing and storage of meat products has always been an important research topic for the meat product processing industry.Traditional antioxidants are cheap and efficient,but long-term or excessive consumption might be harmful to human health.With the improvement of people's living standards and health consciousness,seeking natural antioxidants from plants has become a research hotspot of meat processing.Mulberry polyphenol?MP?is a natural antioxidant which has been proven to improve the quality of meat products and delay the oxidation of products,but its processing stability is poor.Therefore,the present work attempts to build mulberry polyphenol microencapsulate and study its regulation on meat protein oxidation.First,?-cyclodextrin??-CD?was used as the wall material to prepare mulberry polyphenol-?-cyclodextrin-microcapsule?MPM?and its processing properties were evaluated.Secondly,the effects of MPM on the structure and functional characteristics of myofibrillar protein were analyzed through different simulated oxidation systems.Finally,the effects of MPM on the quality and functional characteristics of the dried minced pork slice were investigated.The results are as follows:The effect of different methods,including grinding,ultrasound,ultra-high pressure,magnetic stirring,and homogenization,on the encapsulation efficiency of phenolic compounds were compared,and the results showed that ultrasonic treatment exhibited the best effect on the embedding of phenols.The optimal preparation parameters for MPM were treated by ultrasound at 450 W,25?for 1.5 h with a core/wall ratio of 1:6.Under the optimized condition,the encapsulation efficiencies of the active ingredients including total polyphenols,flavonoids and anthocyanins in the MPM were 97.18%,97.18%,and 97.15%respectively.The existence of microcapsules was verified by UV scanning wavelength absorption,fourier transform infrared spectroscopy?FT-IR?,differential scanning calorimetry?DSC?and derivative thermogravimetry?TG?.After microcapsulatione,the processing stability including light,thermal and storage stability of the MP were remarkably improved.Different oxidation systems,such as feton system,linoleic acid/lipoxygenase system?LOX?and alkyl peroxy radical?ROO·?system were used for the simulated oxidation of myofibirllar protein.Under different oxidation simulation systems,the side chains of myofibrillar protein amino acids underwent different degrees oxidation,among which the LOX system was the most significant.MPM can significantly inhibit the accumulation of carbonyl and disulfide bonds content and the loss of thiol and?-NH₂ content in myofibrillar protein caused by oxidation.Besides,the addition of MPM will lead to the structural changes of myofibrillar protein,mainly manifested as the intensification of the?-helix,the generation of the?-turn and random coil structures.At the same time,the MPM will affect the performance of the myofibrilliar protein thermally conductive gel,which leadss to denser gel structure,and smaller and uniformly pores.Microencapsulation can effectively reduce the adverse effect of MP on the color of the dried minced pork slices,and improve the polyphenols stability of the product.After storage for 28 days atroom temperature,the retention rate of phenolic compounds in the dried minced pork slices with MPM added was 54.55%,which was1.71 times that with MP.Among all samples,product prepared added both MP and MPM showed the highest oxidation stability and polyphenols stability.Besides,the resulted product exhibited good in vitro antioxidant activity.