Strawberry Market Requirements

Handling, packaging, transport and storage is critical and fruit needs to be picked ripe, with good skin and pulp integrity, be free of disease and have an intact calyx and stem.

Processed fruit is used in a number of products including jams, concentrates, syrups, wine, cakes, confectionary, ice cream and preserves. Most processed strawberries are separated from the stalk and calyx in the field prior to packing. They are commonly quick frozen prior to use in the above processes. Generally, upon thawing, frozen fruit loses some of its color and aroma and is less sweet. Fruit is also less firm.

Fresh Strawberry Quality

Strawberry fruit consists of approximately 90% water and 10% total soluble solids. They are a good source of folate and potassium, as well as dietary fiber, manganese and antioxidants. 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.

Most countries have specified grades or standards for the crop (Tables 2 and 3). The top grades are generally more uniform and comprise larger, riper fruits, with minimal defects. They should also be free of disease. Handling and storability is critical and large losses and low shelf life occurs as a result of rots and decays.

Strawberries have very high respiration rates of around 20-40mg CO2/kg per hour at 5oC and this makes them highly perishable. In general they can be kept for 5-10 days, if pre-cooled immediately after harvest, and are stored at 0oC and at 90-95% relative humidity. Berry shelf life can be extended by using 10-30% carbon dioxide in refrigerated transport storage, helping to reduce fungal growth. At CO2 levels above 30%, off-flavors can develop.

The nutrient status of the fruit plays a major role in protecting fruit quality. Too much nitrogen results in excess plant vigor and a larger canopy. This leads to delayed ripening and malformed fruit, a greater incidence of disease and lower soluble solid content, flavor, firmness and a reduced shelf life. The use of a balanced fertilizer programme helps to reduce disease in the fruit through strengthening the skin and also improve shelf life.