| Pine pollen,a medicinal and edible material in China,is the male reproductive cells of Pinus massoniana Lamb.or Pinus tabuli formis Carr.and other plants of the same genus.It has attracted raising concerns from the food and pharmaceutical industries owing to rich nutrients,bioactive compounds and a wide range of pharmacological effects over the world,and it has a broad prospect of development and application.However,the effects of postharvest processing,such as sterilization,wall disruption,extraction,and storage of pine pollen on its nutrients,bioactive compounds and functions are unclear.Therefore,in this study,nutrients and bioactive compounds of pine pollen from different areas were first investigated,then pine(Pinus yunnanensis)pollen was employed as the subsequent research object.The phenolics compounds in pine pollen were identified,the effects of irradiation sterilization and superfine grinding wall disruption treatment on the nutrients,bioactive compounds,antioxidant activity,and storage stability of pine pollen were investigated,and the quality changes of ethanol extract and water extract of wall disruption pine(Pinus yunnanensis)pollen during accelerated storage were evaluated to establish a shelf-life(SL)prediction model,providing the basis for intensive processing of pine pollen.The main contents and results in this study are as follows.The proximate nutrients,mineral elements,amino acids,fatty acids,total flavonoid content(TFC),total phenolic content(TPC),and total triterpene content were analyzed and compared in pine pollen from different areas(Yunnan,Yanji,and Taishan).The results have shown that there was no significant difference in the proximate nutrients of pine pollen from three different areas,but there was a large difference in the mineral content.The contents of total amino acids(TAA)ranges from 86.44 mg/g to 97.33 mg/g,and the highest content of TAA was found in pine(Pinus yunnanensis)pollen.The ratio of unsaturated to saturated fatty acids(UFA/SFA)in three types of pine pollen were 1.97:1,2.34:1 and 2.50:1,respectively.There was no significant difference in total triterpene content,and the highest TFC(1.79 mg/g RE)and TPC(2.16 mg/g GAE)were found in pine(Pinus yunnanensis)pollen.Moreover,eight phenolics were identified in pine(Pinus yunnanensis)pollen,including coumaroylquinic acid,protocatechuic acid,catechin,epicatechin,caffeic acid,p-coumaric acid,naringenin,and taxifolin.The effects of irradiation sterilization and superfine grinding wall disruption treatment on the nutrients,phenolic fractions,antioxidant activity and ?-glucosidase inhibition ability of pine(Pinus yunnanensis)pollen were evaluated.The results have shown that after irradiation,the microstructure of pine pollen has no obvious change;total soluble sugar content increased;TAA and UFA contents have no obvious change.Irradiation contributed to the degradation of insoluble-bound phenolics(IBP),causing the decline of TPC and TFC,while TPC and TFC in soluble phenolics(SP)increased.Total antioxidant activity was decreased by 29.18%-40.90%after irradiation.After superfine grinding wall disruption,obvious fragments were found in pine pollen.Total soluble sugar content was increased;TAA was decreased;UFA was increased.The TPC and TFC in IBP were increased after wall disruption,while they were unchanged in SP.Meanwhile,the total antioxidant activity increased by 46.68%-58.06%.All the fractions from featured pine pollen(FPP),irradiation sterilization pine pollen(ISPP),and wall disruption pine pollen(WDPP)exhibited a high ?-glucosidase inhibitory activity(61.6%-82.8%).After irradiation,the ?-glucosidase inhibitory activity of FP and IBP were increased by 9.09%and 5.17%,respectively;after superfine grinding wall disruption treatment,the ?-glucosidase inhibitory activity of FP was increased by 12.6%,while decreased by 7.2%in IBP.Overall,the combination of irradiation and wall disruption treatments may have maintained or even increased the biological activity of pine pollen,which may alleviate the concern of the reduction of biological activity of irradiated food.Effects of irradiation and superfine grinding wall disruption treatment on main components and antioxidant activity of pine pollen during storage at 55? for 8 weeks were investigated.The results have shown that irradiation slowed the reduction of taxifolin and ascorbic acid levels and the increase of ferric-ion reducing antioxidant power(FRAP),but accelerated the increase of 1,1-diphenyl-2-picrylhydrazyl(DPPH)radical scavenging activity and SFA and the decline of monounsaturated fatty acids(MUFA)in pine pollen during storage.Moreover,superfine grinding wall disruption accelerated the rise of p-coumaric acid and naringenin contents and the decline of taxifolin level,and slowed the increase of SFA and decline of MUFA in pine pollen during storage,while there was no significant effect on the rise of FRAP value and DPPH value.The malondialdehyde accumulation(MDA)in WDPP and FPP was higher than MDA in ISPP after 8 weeks of storage.Overall,irradiation treatment enhanced the storage stability of pine pollen,but the superfine grinding wall disruption treatment increased the content of some antioxidants and MDA in pine pollen during storage.70%ethanol extract and aqueous extract were prepared from wall disruption pine(Pinus yunnanensis)pollen,and their quality changes during storage were investigated by accelerated experimental model and the shelf-life prediction models were established.The results have shown that the higher storage temperature of pine pollen,the faster the oxidative degradation rate of the phenolic compounds in them.The phenolic content and the FRAP values decreased slightly,and the overall stability was good when storage temperature was set at 25?.In addition,the kinetic equation combined with the Arrhenius equation was used to establish the shelf-life prediction models for the ethanol extract((?))and aqueous extract((?))of pine pollen.Both models were validated by out-group model(37?),showing that the predicted values of the model were within 10%error from the actual values,which confirmed the reliability of both shelf-life prediction models. |
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