There are a number of variables that define stone fruit quality requirements. Quality standards differ depending on the stone fruit type, growth region and the market.
Stone Fruit External Appearance
The degree and level of these external factors can make a big difference to crop price and marketability.
Acceptable size and grade varies according to market and most countries set their minimum standards. Splitting, cracking and other physiological disorders are undesirable.
Stone Fruit Taste and Internal Quality
Fruit firmness is particularly important to the bite quality of the fruit. Optimum firmness levels also contribute to a better resistance against physiological disorders (breakdown of fruit flesh, pitting) and fruit rots during storage.
The Vitamin C or ascorbic acid content is perceived by consumers as being beneficial for a healthy nutrition.
Crop Nutrition and Stone Fruit Quality
Calcium has a major role to play in maximizing fruit quality by providing firm fruit, with minimal internal breakdown or rots and tougher skin. Calcium also increases TSS and sugar content, flavour, taste and juiciness.
Potassium has a major role to play in improving fruit quality by boosting the TSS content and colour of fruit. However, supplies need to be in balance as over-availability can lead to other quality problems due to competition between K, Ca and Mg uptake.
Increasing nitrogen supply can increase fruit acidity, improving vitamin C contents. However, overuse of N delays maturity, softens the flesh and thins the skin. It can also reduce fruit colour and TSS contents. This is due to the improved yield and larger fruit size, which dilutes the level of TSS in the fruit.
Phosphorus increases fruit colour by boosting anthocyanin content. It also helps minimize a range of storage disorders.
Iron is important in boosting growth and, as a result, maintaining fruit fill and sugar content.
Boron and copper help improve skin strength, minimizing cracking.