What is a quality apple?

“Fruit quality” is a dynamic concept that changes based on consumer needs and perceptions, reflecting socio-cultural evolution. Consumers find apples in two ways: 1. Based on its appearance (color, size, shape, absence of defects) 2. By eating.

Apples are grown all over the world in temperate, subtropical, and tropical environments. More than 63 countries produce apples with a wide variety of growing conditions and use a large number of varieties. With a production of 84 million tons in 2014, apples are the fourth most important fruit produced and consumed worldwide (after citrus, grapes, and bananas). The modern apple we consume is probably the result of interspecific hybridization (Malus × Domestica Borkh).

Definitions of quality

To begin, let’s review the many definitions of quality that researchers have presented over the years:

• Quality is a word with different definitions, and this concept is echoed by terms such as genuineness, specificity, and product freshness.
• The sum of all the features and characteristics of a product or product to meet the specified or hypothetical needs of the consumer.
• A set of factors such as external features (market value), technological features (conversion value), internal features (nutritional value), image value (based on psychological and irrational concepts), and sensory value (organoleptic traits).
• The standard for the specific use of the product (“Industrial quality”, “Nutritional quality”, “Export quality”, “Edible/consumer quality”).

In general, fruit quality includes a wide range of external and internal traits. The external quality of the fruit includes color, shape, size, and the absence of defects.  Internal quality includes taste, texture, aroma, nutritional value, sweetness, acidity (which plays a role in taste), shelf life and there is no defect. Commercial standards determine the quality of apples in Europe and the United States. The most important factors are size, color, integrity, smooth skin and no russet.

External quality factors

Now we study some of the factors affecting the external quality of apples.

Appearance: The appearance of fresh fruit is the first component of purchase that influences the consumer’s decision to consume. The concept of “appearance” includes several external characteristics of the fruit, such as size, shape, lack of defects, and color.

Size: Fruit size is a function of cell number, cell volume, and cell density. Small fruits contain fewer and smaller cells than large fruits and are usually cheaper. Larger fruits are mostly selected for faster consumption because they are less durable in terms of storage.

Color: Green, yellow and red colors of different types of apple color. In general, red is preferred, even if dark red is less popular, while bright red apples and new alternative colors have recently attracted consumer attention. Fruit color preference can be different in each region. The intensity of the red color of apples for consumers is a measure of sweetness (Sugar) and higher quality. Of course, for some apple varieties, being too red is a negative factor for consumer choice. Research has shown that too red, although more preferred by consumers, cannot be a measure of apple maturity, but should be considered alongside other quality indicators.

Russeting: Russet is characterized as a physiological disorder characterized by brown areas and cork on the surface that begin in the early stages of fruit development. Russeting has a related economic impact because it reduces the quality and commercial value of apples. Russet fruit not only reduces its value in fresh markets but also reduces its shelf life.

Internal quality factors

Texture and firmness: The most preferred texture traits of consumers are apple firmness, juiciness and lack of mealiness. Fruit firmness is mainly used commercially to determine the optimal harvest time. The range of stiffness usually varies depending on the variety, location, and stage of maturation, so specific tables have been developed in the industry that serve as a reference for determining the best time to harvest. The more mature the fruit, the less firm it becomes. Firm fruits usually have denser textures and can be stored longer than soft fruits.

Soluble solids: One of the important properties of the internal quality of the apple is its sweetness. Since sensory evaluation of sweets is not always easy, it can be determined as a tool by measuring the total sugar content. The sugar values for each apple variety can vary from year to year, from garden to garden and between picking dates. Therefore, the minimum-maximum range of values can be used as a reference, but there is no absolute value to identify each one.

Acidity: Acidity (or sourness) is an essential characteristic of the internal quality of the fruit that indicates the sensory intensity of the total organic acid content. The sour taste of apples is created by organic acids. The acids also influence the perception of sweetness and contribute to the intensity of the taste. The acid content of apples is very important for the quality of fruit eating where both low-acid and high-acid apples are considered undesirable. The total organic acid content of apples is important not only for the experience of eating and its correlation with the taste of apples but also because organic acids are the substrate for fruit respiration inside and outside the tree.

Conclusion

Future apple-growing plans around the world focus on increasing domestic quality concerning resistance to major diseases. Quality is a relative concept and the criteria for evaluating and paying attention to it depend on the thinking of people in the horticultural supply chain. Despite extensive advances in fruit quality assessment, the most important factor in fruit selection is its color.  The real goal of gardeners should be to define common and universal standards for apple quality, including organoleptic and nutritional value.

On the other hand, the fruit industry and the marketing department can teach consumers about the internal characteristics of the fruit and make them more aware so that they do not limit themselves to the appearance of the fruit.

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Doi: 10.1016/j.scienta.2017.12.057

Link: https://www.sciencedirect.com/science/article/abs/pii/S030442381730780X