Abstract:
Potatoes have been one of the most important food crops in the world, due to their rich in starch, vitamins, and minerals. Their strong adaptability and short production cycle can greatly contribute to agricultural products globally. However, the storage of potatoes can often confine to the germination of tubers with irregular shapes and sizes. Physical and chemical approaches have been utilized to inhibit potato germination. Various metabolic pathways can involve significant physiological and biochemical alterations after harvest. The primary germination of potato tubers can also be dominated by enzymatic activities, carbohydrate metabolism, and hormonal regulation. Since the chemical inhibitors can effectively prevent sprouting, their use can often result in environmental contamination and potential food safety concerns. Although the low-temperature storage can effectively suppress sprouting, it can inadvertently promote undesirable saccharification to alter the color of processed potatoes. The harmful compounds can also be formed with carcinogenic risks, such as acrylamide. This study aims to prevent tuber infection and nutrient loss caused by potato germination during storage. The low-temperature plasma jetting was utilized to inhibit potato germination. A one-way experiment was conducted to determine the optimal influencing range of the plasma treatment voltage, gas flow rate, and treatment time on potato germination and weight loss. The box-Behnken response surface method was used to optimize the interaction levels among the three influencing factors (plasma treatment voltage, gas flow rate, and treatment time). The optimal conditions were then obtained for the plasma inhibition of potato germination. A systematic comparison was made on the SOD, CAT, POD, and PPO antioxidant enzyme activities between the optimal plasma treatment and the blank control group. The optimal plasma treatment was obtained on the potato quality indexes. The results showed that the optimal parameters were achieved for the plasma treatment of potatoes, including the voltage of 18 kV, treatment time of 20 s, and gas flow rate of 13 L/min. The germination rate and weight loss rate of potatoes were significantly reduced to 31.42% and 2.15%, respectively. Compared with the blank control group, the plasma treatment group significantly increased the activities of potato antioxidant enzymes (CAT, and SOD). The SOD and CAT activity of the plasma-treated group increased by 52.63% and 29.27% (
P<0.05), respectively, after 16 days of storage, compared with the control; Furthermore, the POD and PPO activities of the treated group increased by 8.69% and 18.58%(
P<0.05), respectively, compared with the control. Compared with the blank control, plasma-treated group increased the hardness and brittleness of the potatoes. Specifically, the hardness of the treated group increased by 6.06% (
P<0.05). While the brittleness of the treated potatoes was reduced by only 24.00% within 16 days, compared with 37.19% in the control. In addition, the plasma treatment reduced the sugar accumulation and dry matter consumption, thus maintaining the storage quality of potatoes. Among them, the reducing sugar was reduced by 32.56% in the treated group (
P<0.05), compared with the control. The dry matter increased by 7.66% in the treated group. Therefore, the plasma treatment can be expected to effectively inhibit and then slow down the germination process of potato tuber. The finding can lay a foundation to reveal the inhibiting mechanism of plasma technology from potato tuber germination.