Citrus market requirements

Fresh fruit

Consumers are influenced by flavor and taste as well as by the shape and appearance of the fruit. Oranges need to be sweet with bright orange peels. Mandarins should be easy to peel and red-orange in coloration. With lemons, a bright color and shape are important – most consumers prefer a lemon that is not too elongated or round.

Peel thickness is also an important quality parameter. This influences transport quality, peelability and oil production characteristics. Thicker peels provide higher levels of oil extraction and offer a greater resistance against pests and better storage/shipping ability. In the fresh fruit market a thicker peel is regarded as being easier to peel. Excessively thick peel is undesirable.

Provided internal quality is acceptable, some markets are less influenced by skin blemishes. The trend to have seedless fruit for fresh consumption is increasing.

Flavor and taste is related to the level of Total Soluble Solids (TSS), acidity and the amount of aromatic or bitter flavors in the fruit. A measure of the TSS content is usually obtained from assessing the °Brix of the fruit.

In the USA, a minimum TSS/Acid maturity ratio of between 7 to 9:1 is normally desired for oranges and mandarins. In Spain the minimum is 6:1, for satsumas and early oranges and increases to 8:1 for ‘Fortune’ mandarins. For grapefruit between 5 to 7:1 is the standard for marketable produce.

For lemons, the level of acidity is particularly important. Lemon varieties have between 5-7% (mostly citric acid), compared with around 1% in oranges.

In tropical climates, harvesting of oranges commences when the minimum TSS/Acid ratios (defined above) are reached and the fruit has a green-yellow color on no more than 25% of its surface. In Mediterranean climates, fruit is harvested when the appropriate TSS/acid ratio is reached and the fruit is orange across its complete surface. Exceptions in fruit color may be made in early fruit harvests, however this fruit may be ‘de-greened’ in ethylene chambers.

Lemons are deemed ripe when a certain juice percentage is obtained. In New Zealand, for example, this is 25-35% for lemons and 45-50% for limes. In Spain the minimum juice content for lemons is 30 to 40%.

Acceptable size and grade varies according to market, and most countries set their minimum standards.

Splitting, creasing and other physiological disorders are undesirable. Correct potassium and calcium nutrition is critical to minimize the risks of producing these off-grades.

Processed fruit

Although yield is often the main focus when growing citrus for processing, juice quality is also important and crops are assessed for TSS and Acidity.

The TSS/Acid ratio provides an indication of the taste of the fruit - sweet or bitter. The minimum maturity values for oranges vary during the season and according to country and region.

The lower the TSS/Acid ratio the more sweeteners are added to achieve acceptable taste. Sweetened juices are labeled as such and receive lower prices.

Juice color is also important and countries have specified color range scores that are required for premium marketability.

The thicker the peel, the lower the proportion of the edible fruit and the lower the relative juice content, leading to lower juice extraction levels for the processing industry.

Fruit must in general have no cuts, decay or bruises, which are likely to adversely affect the juice segments.