PINEAPPLE TRANSLUCENCY ISSUE

TRANSLUCENCY is a recurring problem for pineapple industry. Translucent fruit contained more sucrose, glucose and fructose in apoplast than those in apoplast of normal fruit. There were more liquid in intercellular space of translucent fruit than that of normal flesh. The contents of alcohol and ethylene in translucent fruit were higher than those in normal fruit. Translucent fruit contained less calcium than normal fruit. Electrolyte leakage of translucent flesh was more than that of normal flesh. There were 205 proteins of which the expressions in translucent flesh were higher than those in normal flesh. Calcium-ions-binding protein EF-hand domain-containing protein, ethylene-synthesizing enzyme 1-aminpcyclopropane-1-carboxylate oxidase, ROS-producing protein universal stress protein A-like protein were the top three proteins of which the expressions in translucent flesh were higher than those in normal fruit. When much sugar was transferred into fruit pulp and accumulated in intercellular space, water will be absorbed from cells around and translucence formed. The accumulation of sugar and liquid in apoplast were due to that cell wall and membrane were degraded, which was from being attacked by ROS. There might be more and larger pores in cell wall and membranes of translucent flesh. These data played foundations for scientist researching methods for controlling pineapple translucency. There are about 17,805 hectar area in Malaysia grown with pineapple in 2023 producing for 553,348 metric ton. Most area planted with pineapple are in Johor with 11,399 hectare (producing for 402,555 mt) followed by Sarawak (2,289 ha) and Pahang 1,362 ha). This article in "Anim Agriculture Technology" I share an information about occurrence of translucence issue fo pineapple. 

Pineapple (Ananas comosus L. Merr.) is an important crop in tropical- and subtropical-countries. Pineapple translucency (or water core) is a recurring problem for marketing fruit. Flesh of translucent pineapple has a water-soaked appearance. The intercellular spaces in translucent flesh are filled with liquid. Translucent fruits are fragile and prone to mechanical damage during harvest and postharvest handling. They had poor flavor and significantly lower edible quality. Issue of tineapple fruit translucency affects about 10% of fresh fruit and losses can exceed 30%. Pineapple translucency had close relationship with calcium deficiency, fruit temperature and the size of crown. Fruit translucency index decreased as the amount of calcium applied was increased. It was more severe when maximum and minimum temperature 3 months before harvest were lower than 23˚C and 15˚C respectively. Covering fruit with clear-plastic during the last 3 weeks of fruit development increased translucency severity. Fruit with larger crowns had lower incidence of translucency. Sugar content is an important component of pineapple quality. Chen and Paull (2000) found that sucrose and fructose in pineapple fruit increased rapidly since 4 weeks before harvest. Removal of 1/3 of the plant leaves 3 weeks before harvest significantly reduced fruit flesh total soluble solids and translucency incidence at harvest. Removal of crown increased translucency. These suggested that sugar accumulation in fruit had relationship with pineapple translucency. Increased apoaplstic solute sugar concentration and water movement into apoplast may lead to pineapple translucency. However, whether these processes did have happened in translucence fruit is to be identified. The mechanism underlying pineapple translucency was still unclear. In this research, sugar contents and volumes of appoplastic liquid showing water movement in translucent fruit and normal fruit were compared. The activities of cell wall invertase, an enzyme that can transform sucrose into glucose and fructose, were also measured. To understand the mechanism underlying pineapple translucency in whole scale, proteomes in translucent fruit and normal fruit were also analyzed. Results showed that the contents of sucrose, glucose, fructose and total sugar in translucent flesh were similar with those corresponding values in normal flesh. But the apoplastic contents of sucrose, glucose, fructose and total sugar in translucent flesh were significantly higher than those in normal flesh. The activity of cell wall invertase (CWI) in translucent flesh was higher than that in normal flesh. More sucrose was transformed into glucose and fructose in translucent fruit than normal fruit. Translucent fruit contained more liquid in appoplastic space than normal fruit. There were 205 proteins of which the expressions in translucent flesh were higher than those in normal flesh. There were 10 proteins whose expressions in translucent flesh versus those in normal pineapple fruit (W/C) were more than 5.6. The W/C of 1-aminocyclopropane-1-carboxylate oxidase (ACO) was 11.9. Ethylene in translucent fruit was significantly higher than that in normal fruit. Translucent fruit contained more ethanol than normal fruit. There might be more reactive oxygen species (ROS) in translucent flesh than those in normal flesh, which can attack cell membrane/wall and result in more liquid released from cells. Electrolyte leakage of translucent flesh was significantly higher than that of normal flesh, there might be more pores in cell membranes of translucent flesh or the diameters of pores in cell membranes of translucent flesh were larger than those of normal flesh. There were much more liquid accumulated in intercellular space of translucent flesh than that in normal flesh in which may results in pineapple fresh fruit translucency. This is the first paper demonstrating the relationship between sugar accumulation in appoplastic space and pineapple translucency. The mechanism underlying pineapple translucency was also proposed. Thanks.

By,

M Anem,

Taman Cendana,

Melaka, Malaysia.

(Jun 2024).