Optimization of hot air and microwave combined drying process for barley seedling powder
Abstract: Objective To explore the rapid drying method of barley seedling powder. Methods The drying process of barley seedling powder was studied by hot air drying and microwave drying equipment. The effects of hot air temperature, microwave power and water cut rate on the content of chlorophyll and total flavonoids in the drying process were investigated.
Results The optimum combined drying conditions were: hot air temperature 66.2 °C, microwave power 231 W, conversion point moisture content 50.91%, the chlorophyll content was (6.006±0.192) mg/g, and the relative error with the theoretical prediction was -0.77%; the content of total flavonoids was (5.695 ± 0.145) mg / g, and the relative error from the theoretical prediction was -1.18%. Compared with hot air drying, the nutrient content of the combined dried barley powder increased by 3.69% and 13.04%, respectively, and the drying time was shortened by 22%. Conclusion Combined drying with hot air and microwave is a better method for drying barley seed powder, which provides a scientific reference for the drying process of barley seed powder.
Key words: barley seedling powder microwave drying; hot air drying; combined drying; response surface analysis
The annual herb of the genus Hordeum is the fourth largest grain in the world after wheat, rice and corn. It is also one of the main cereal crops in China. According to the Ming Dynasty Li Shizhen's "Compendium of Materia Medica" records that "barley is sweet, flat, has a diet, swelling, wide chest, tonic, strong blood, benefit color, real five internal organs, and the benefits of the food."
Barley seedlings are seedlings of gramineous plant barley. They are homologous crops of medicine and food. They have many physiologically active substances and contain a variety of essential amino acids. They are rich in antioxidants such as superoxide dismutase, vitamin C and flavonoids. Etc., is the health care product resource with the richest, most balanced and most suitable nutrients in the world's single resources, and has many physiological functions such as anti-oxidation, anti-tumor, detoxification, anti-inflammatory and cancer prevention. Therefore, it has received extensive attention from consumers and scholars at home and abroad.
The moisture content of barley seedlings is as high as 90% or more, and it is not easy to store for a long time under normal temperature conditions. Drying is an important technical means for long-term storage of agricultural products. The common method for drying barley seedlings is hot air drying. The operation is simple and the investment is small, but there are also shortcomings such as long drying time, low efficiency and poor quality. In recent years, microwave drying technology has been widely used in the food industry due to its advantages of fast drying speed, energy saving, convenient operation and no pollution.
At present, there are few reports on hot air drying and hot air-microwave combined drying of barley seedlings at home and abroad. Therefore, this paper applies hot air drying and hot air-microwave combined drying technology to study the dehydration process of barley seedling powder, explores the method of joint drying, explores the effect of different drying processes on the quality of barley seedling powder, and provides industrial drying production of barley seedling powder. Scientific reference.