Research On Evaluation Of Post-ripening Quality And Processing Characteristics Of Avocado

Avocados are rich in various nutrients and have a variety of physiological health functions.China has become a major consumer of avocados in the world,importing 32,100tons in 2017.However,avocados belong to the category of respiratory metamorphosis fruit.The storage period is short under normal temperature condition,and the fruit quality change is difficult to control.At the same time,there are few studies on the storage quality and processing characteristics of avocados at room temperature in China,which greatly restrict the development of Chinese avocado industry.Therefore,it is the key to promote the development of the avocado industry to explore the physiological changes of avocados after normal temperature,master the changes of avocados'quality and processing characteristics after normal temperature,and explore the efficient and safe production and processing of avocados.In this paper,“Hass”avocado was selected as the research object to study the changes of its physiological characteristics,sensory characteristics and pulping characteristics under the condition of normal temperature.At the same time,the effects of different water addition and ultra-high pressure treatment on nutrient quality and sensory quality of fruit pulp were investigated.The main research results are as follows:?1?Under normal temperature?25??,avocados appeared climacteric after ripening 3 d,and colour,hardness,sensory quality are all related to the changes of breathe;as time extends?>3 d?,the pulp,peel,and core can completely peel,hardness fell to best edible value?4.4⁶.7 N?,the skin color changes from green to black,grass disappeared,nuts,butter increase and can make uniformity,stabilized puree.When a*<4,the logistic equation of a*can accurately predict the storage time of avocados.?2?Water addition in the pulp preparation process can effectively improve the pulping condition and rheological properties of the avocado pulp.The pulp has pseudoplastic fluid behavior.The viscosity of the pulp decreases with the increase of shear rate from 1 s^-11 to 100s^-1.The viscosity of pulp decreases with the increase of dilution ratio,water addition can reduce starting viscosity.The content of dry matter,pH value,total phenol content and DPPH scavenging ability in fruit pulp decreased with the increase of dilution ratio.?3?Ultra-high pressure treatment can inactivate the microorganisms in the pulp,which is limited to the pH value of the pulp?close to neutral?,and when the pressure exceeds 500 MPa,the total number of fruit pulp colonies can be ensured to be less than 100 CFU/mL?GB 7101--2015 national standard for food safety beverage?.The color,rheological properties and sensory quality of fruit pulp were not affected by UHP treatment.The total phenol content,PPO enzyme activity and DPPH scavenging capacity in fruit pulp increased first and then decreased with the destruction of cell membrane structure under treatment pressure,while the pH value of fruit pulp decreased continuously.Based on the above,it can be seen that with a series of physiological and biochemical effects in the process of storage at room temperature,avocados gradually reach edible and processable maturity from picking maturity.The avocado can be processed and made into pear pulp after 3-6 days of ripening.At this stage,the pulp is uniform,delicate and stable.Water addition can effectively reduce the resistance in pulp pulping process and eliminate the phenomenon of pulp hanging on the wall,can reduce the initial viscosity of fruit pulp,better for fruit pulp making and delivery.The UHP treatment will not affect the color,sensory quality and rheological properties of the pulp.When the pressure exceeds 500 MPa,the total number of fruit pulp colonies can be ensured to be less than 100 CFU/mL..