控制桃果实采后病害拮抗酵母的筛选及其固体制剂的制备

Selecting Antagonistic Yeast for Controlling Postharvest Disease of Peaches and Producing Solid Preparation

通过体内实验筛选对桃果实采后软腐病具有控制作用的拮抗酵母菌,并考察其对桃果实自然腐烂的控制效果及对桃果实品质的影响。通过单因素试验优化喷雾干燥法制备拮抗酵母固体制剂的条件,并考察保存90 d的固体制剂对桃果实采后软腐病的控制效果。结果表明,膜醭毕赤酵母(Pichia membranaefaciens)处理的桃果实贮藏72 h后,软腐病造成的腐烂率(26.23%)显著低于对照(95.70%)。该拮抗酵母还可显著降低桃果实采后自然腐烂,且对其品质无显著不良影响。制备固体制剂的优化条件为:保护剂阿拉伯胶与海藻糖的质量比1∶1、保护剂质量浓度100 g/L、雾化器压强200 kPa、进风温度100℃、进料速率15 mL/min。制备的固体制剂在25℃和4℃保存90 d后,酵母存活率分别为66.97%和82.91%。4℃保存90 d的固体制剂处理的桃果实软腐病腐烂率(37.04%)与新鲜制备的拮抗酵母处理的桃果实腐烂率(31.48%)虽有显著性差异,但控制效果仍然非常明显。

An antagonistic yeast for controlling Rhizopus rot of postharvest peaches was selected by in vivo tests. Then its biocontrol efficacy against natural decay of peaches and its effects on the quality of peaches were investigated. The conditions for producing a solid preparation of this antagonistic yeast by spray drying method were optimized by singlefactor experiments and after being stored for 90 d, the obtained preparation was used to control Rhizopus rot of peaches. The results showed that the decay incidence of 72 h-stored peaches caused by Rhizopus rot was decreased by Pichia membranaefaciens(26.23%) compared with that of the control(95.70%). The antagonistic yeast also evidently reduced the natural decay incidence without adverse effect on the quality of peaches. The optimized conditions for producing the solid preparation were as follows: gum Arabic-to-trehalose ratio 1:1(m/m);protectant concentration 100 g/L, atomizer pressure 200 kPa, inlet air temperature 100 ℃, and feeding speed 15 mL/min. The survival rates of this yeast strain in the obtained solid preparation were 66.97% and 82.91%, respectively after being stored at 25 and 4 ℃ for 90 d. The biocontrol efficacy of the solid preparation stored for 90 d at 4 ℃ was very obvious, although the decay incidence(37.04%) was significantly higher than that obtained with the freshly prepared yeast suspension(31.48%).