Influencing Strawberry Quality
The fruit is high in vitamin C and consumption of 10 fruit per day virtually meets all of the recommended dietary requirements for this vitamin. The main soluble sugar components are glucose and fructose. The primary acid is citric acid. Strawberry flavor is a key characteristic and is a complex mix of the sweetness, acidity and aroma of the fruit. The most intensely flavored fruit have a high TSS and also acidity.
The best quality berries are uniform in size and should be glossy with a strong red color. They should also be juicy and have a strong aroma with no mold or bruises. Variety selection is critical and each cultivar has its own often distinctive shape, size, taste and texture. Fresh strawberries are harvested and stored with the calyx and part of the stem intact, which is then removed by the consumer prior to eating. Size is important, but overly large fruit are more difficult to package and transport. Small differences in fruit quality can have a strong impact on price and grade, so production methods focus on producing and maintaining good quality fruit with a long shelf life.
Variety selection is particularly important and producers should select resistant cultivars with the quality characteristics that most suit their intended market. Use of appropriate mulches or growing systems to minimize soil contamination is important to physical quality. Good hygiene, sanitation and appropriate in season fungicides and pesticides will help to provide fruit that is less at risk of pest and disease damage. Maximizing growth through appropriate irrigation will help ensure good water and nutrient flow to the developing fruit. Refrigerated storage and transport, utilizing controlled carbon dioxide environments will help to maximize the shelf life of the fruit that is picked. Good crop nutrition will ensure the production of fruit that handles well and has a longer shelf life with the right balance of sugars and acidity plus a good aroma and taste.
Crop Nutrition and Strawberry Quality
Many required nutrients have specific roles to play in improving quality:
- Potassium plays a key role in increasing fruit sugars, acidity and improving its taste
- Nitrogen – particularly nitrate forms – used at adequate rates during flowering and fruiting – will maintain taste and acidity without encouraging rots
- Calcium – is essential to maintain fruit integrity, health and a longer shelf-life, with reduced damage when handling
- Boron – also helps to maintain good fruit strength
Boron
Boron plays a key role in fruit quality with poor supply leading to smaller, malformed fruit.Nitrogen
Excess nitrogen during fruit growth and development has an adverse effect on fruit quality. It increases disease susceptibility and the softening of fruit. This leads to a shorter shelf life and fruit that is quicker to rot. Maturity can also be delayed and fruit malformed, resulting in reduced yields.
Excess N also encourages anthracnose crown rot. Fertigation can help ensure that applied nitrogen is better utilized by the plant and not available to encourage rots. Although, even under more controlled fertigation systems, high N rates may still result in greater disease severity.
