What causes eggplants to taste bitter?
1. Variety factors
Eggplants themselves contain some special bitter substances, such as solanine glycoside M (C31H51NO12) and others. Wild eggplants usually have small, bitter fruits; after cultivation and domestication the bitterness is reduced, but a certain content still remains. The content of bitter substances varies to some degree among different varieties, and the amount of these substances determines, to a certain extent, how bitter the eggplant is. Generally speaking, green eggplants have more than purple eggplants, and short eggplants have more than long eggplants.
2. Influence of environmental factors
The amount of bitter substances in eggplant fruits is largely influenced by the external environment. Protected cultivation is a kind of counter-environment cultivation, and the conditions it creates, affected by the current production level, can hardly reach the optimal environment for eggplant growth.
3. Influence of grafted rootstock
In recent years, to prevent continuous cropping obstacles, many protected cultivations of eggplant have adopted grafted seedlings. Using grafted seedlings can relatively effectively prevent continuous cropping obstacles, but if an unsuitable rootstock is chosen, it will affect quality and sometimes worsen the bitterness of the eggplant.
4. Improper cultivation measures
Eggplant is a fruit vegetable, and its growth requires complete fertilizer. Especially after it shifts from vegetative growth to reproductive growth, the plant's demand for certain mineral elements increases markedly. If nitrogen fertilizer is applied excessively during this period, it easily causes excessive vegetative growth and produces bitterness. In addition, during eggplant cultivation the water supply must be timely; if the water supply is lacking, it will affect the plant's normal physiological and biochemical activities, hinder the transformation and accumulation of dry matter and the decomposition and release of harmful substances, resulting in thick, hard fruit skin, bitter fruit flesh and reduced quality.