What Are The Preharvest Factors That Influence Texture In Fruit

This review examines both the preharvest, and the postharvest factors which influence texture in fruit. Texture is an important aspect of eating quality for consumers. Texture is often overlooked by consumers unless it is markedly different from what is expected from the product (Szczesniak et al). In the case of an unexpectedly unpleasant texture, customer satisfaction is significantly impeded. Consumers use texture as an indication of the state of food to determine whether or not it is good to eat. This marks the importance of establishing optimal texture during preharvest fruit development, and maintaining optimal texture during storage.

There is no consistently used definition of texture in the scientific world despite the ubiquitous use

One of the key factors which facilitates cell extension is prolonged cell wall tension above a certain critical value. The other factors of cellular extension are cell membrane permeability for the flux of water and biochemically mediated making and breaking of cell wall component bonds and these factors will be discussed later. The role of turgor pressure in cell expansion is most important in the early stages of fruit development. During ripening, cell walls in fruit such as the tomato soften without significant cell expansion and turgor pressure is not considered to be a contributing factor (Coombe 1972). Prolonged water stress during fruit development influences textural quality in fruit. The most significant effect of prolonged water stress is reduced fruit growth and yield as shown in soil water deficit experiments with tomato in a Mediterranean climate by Patenè et al. Tomato plants grown with no irrigation had a °Brix content of 6.35 and a firmness of 4.64 kg/cm2 while fully irrigated tomato plants had a °Brix content of 4.90 and a firmness of 3.22 kg/cm2. Firmness is generally associated with ‘good’ textural quality but the reduced fruit size associated with prolonged water stress translates to undesirable toughness with a lack of

The most notable nutrients influencing textural quality in fruit are nitrogen, potassium, calcium, and phosphorous. Experiments by Blanpied et al (1978) evaluating the effects of nitrogen fertilization on Golden Delicious apple firmness showed a 20.07% lower firmness at harvest in apples from trees fertilized with 1.36kg Nitrogen versus apples from trees with no nitrogen fertilization. Reduced fruit firmness due to excessive nitrogen application also occurs kiwi fruit (Prassad et al 1988). However, peaches grown with high levels of nitrogen had smaller cells and greater firmness than peaches grown with lower nitrogen levels (Reeves et al 1970). Low phosphorous and low magnesium levels have been shown to exacerbate reduced firmness attributed to low calcium levels in apples (Sharples 1984). Physiological disorders affecting texture are commonly associated with high (e.g. blossom end rot in tomatoes) or low (e.g. goldspeck in tomatoes) ratios of potassium to calcium. Calcium is considered to be the single most important plant nutrient in terms of texture and shelf life. Calcium cross links with pectins in the cell wall by ionic bonds between C’6 carboxyl groups of galacturonosyl residues. Calcium is thus directly involved in the structure of cell walls and its role in textural quality is clear. Salt accumulation in greenhouse growing media and poorly prepared nutrient solutions can result in poor calcium