Effects Of Different Harvesting Periods On Storage Quality And Synthesis Of Octanol Compounds In Shiitake Mushrooms

Shiitake mushroom is the second largest edible mushroom in the world,which is rich in nutrients and a variety of bioactive substances.After harvesting,shiitake mushrooms undergo vigorous physiological metabolic activities which will change their nutritional quality and aroma components.Harvest maturity is closely related to the storage quality of shiitake mushrooms.At present,there are few studies on harvest maturity on storage quality and flavor of shiitake mushrooms.In this experiment,three harvesting stages(S1: young mushroom stage;S2: mature stage;S3: overripe stage)of Shiitake mushroom were selected and stored at 4℃ with a relative humidity of about 85% to investigate the effects of different harvesting stages on the quality and synthesis of octanol compounds during storage of Shiitake mushroom.The results were as follows:1.Different harvesting periods affect the storage quality of shiitake mushroomsThe changes in sensory,texture,nutrient content and antioxidant activity of shiitake mushrooms in three harvesting periods were studied.The results were as follows:(1)In terms of sensory performance,the young mushroom stage showed the best performance during storage,with the browning index varying from 58.21 to 81.61 during storage;the ripening stage was the second best,with the browning index varying from 59.90 to 85.19 during storage;the overripe stage showed the worst performance,with the browning index varying from 67.23 to 95.99.(2)In terms of texture,the hardness was highest in the young stage(317.86 g)on the day of picking,followed by the second hardness in the ripe stage(287.10 g)and the lowest in the overripe stage(257.22 g).Relatively high hardness could be maintained at the young and ripe stages in late storage,while the hardness values at the overripe stage were lower.(3)In terms of nutrient content,the young stage showed lower nutrient content and higher weight loss during storage due to higher respiration rate in the pre-storage period.The overripe stage had high levels of ascorbic acid(13.89 mg/100g),total phenols(0.73 mg/g),and soluble sugars(21.71 mg/g)in the first 5 d of storage,but these nutrients were rapidly depleted in the subsequent storage.On the other hand,mature stage maintained a high nutrient content in the later storage period.And the mature stage showed higher antioxidant activity in the later stage of storage.In conclusion,the shiitake mushrooms harvested at the mature stage have higher storage tolerance and commerciality.2.Different harvesting periods affect the synthesis of octanol compounds in shiitake mushrooms during storageChanges in the content of octanol compounds and their synthetic substrates and synthesis-related enzyme activities during storage of three types of harvesting shiitake mushrooms were studied with the following results:(1)A total of four octanol compounds were detected,and 1-octen-3-ol accounted for the highest percentage of total octanol compounds.The total octanol compounds varied among the three harvesting stages,with a high level in the early stage of young mushrooms,18.45 μg/g at the 5th day of storage,and a peak level of 17.53 μg/g at the 10 th day of storage in the mature stage,which was maintained at a high level in the later stage of storage.The total octanol content remained relatively low throughout the storage period during the overripe stage.In addition,some volatile flavor substances such as aldehydes,ketones,and esters also showed different trends during storage.(2)There were differences in the changes of unsaturated fatty acid content during storage of shiitake mushrooms in the three harvesting periods.The shiitake mushrooms harvested at maturity remained 1037.96 μg/g at the 10 th d of storage,which laid the foundation for maintaining a high octacosanol compound content in its later stages.The LOX activity of young mushrooms reached a peak of 3.20 U/g at the 5th d of storage,but decreased significantly thereafter.HPL and ADH,also synthesis-related enzymes of octanols,expressed different activity levels during storage in the three harvesting stages.The results showed that the harvesting period was one of the factors affecting the content of octacosanol compounds in shiitake mushrooms during storage.In summary,the results indicated that harvesting period is an important factor affecting the quality of shiitake mushrooms,and mushrooms harvested at maturity have higher storage resistance and merchantability,and better retention of flavor components.The harvesting period can influence the synthesis of octanol compounds by affecting the flavor synthesis substrate content and synthesis-related enzyme activities.