Research of the vacuum low-temperature frying process Pleurotus eryngii

Abstract

Mushrooms are consumed because of their nutrients and therapeutic bioactive compounds, historically used in medicine, and representatives of the genus Pleurotus are edible species rich in dietary fibre, vitamins, micro- and macroelements, and carbohydrates. The aim is to theoretically substantiate the vacuum frying of oyster mushroom pieces and to obtain a crispy product with optimal consumer characteristics. In the course of the study, the methods of vacuum low-temperature frying, organoleptic study, orthogonal test, single-factor and statistical analysis were used. The factors affecting the quality of vacuum roasting of oyster mushrooms: pre-drying time, temperature and roasting time are analysed. The relationship between oil content and sensory evaluation is described and analysed. The optimal technological parameters of vacuum frying were determined. Pleurotus eryngii with a thickness of 2 mm were completely inactivated under boiling conditions for 90 s at 80℃, and for 10 s at 90 and 100℃. If prolonged cooking takes place, the oyster mushroom texture becomes soft and is not amenable to further processing under vacuum at low temperature. Therefore, in order to save production energy and reduce the loss of flavour and nutrients, cooking at 80°C for 90 s was chosen. It has been shown that the treatment of Pleurotus eryngii with maltodextrin before vacuum frying reduces the oil content after frying, provides a homogeneous structure, good taste and crispiness of the product. Optimal parameters were obtained: 2 mm slices, mass fraction of maltodextrin 15%, sonication duration 15 min. The influence on the sensory evaluation of the primary and secondary order is described: frying temperature > pre-drying time > frying time. The specific parameters for which the product will obtain the best sensory characteristics were indicated, namely: frying for 10 min, pre-drying for 20 min, frying temperature of 90℃. The factors influencing the oil content were analysed: pre-drying time > frying time > frying temperature. It was found that the product can obtain the lowest oil content when pre-drying for 30 minutes and frying at 80°C for 10 minutes. The practical value of the study lies in the optimal conditions of the process under investigation: pre-drying time with hot air 20 min, frying temperature 80-90°C, frying time 10 min, frying vacuum 0.08-0.09 MPa