Effects of Ripening Stage, Temperature, and Film Wrapping on the Elasticity Index as Determined by a Nondestructive Resonance Vibration Method and Fruit Quality in ‘Irwin’ Mango

Abstract

<jats:p>We examined the effects of ripening stage, temperature, film wrapping, and storage period on the elasticity index (EI) and fruit quality of ‘Irwin’ mangos to develop a storage technique for improving the storage life of this fruit and to determine whether flesh firmness can be estimated using the EI. The second resonant frequency measured between the two sides of the fruit was nearly equal to measurements between the dorsal and ventral surfaces of the fruit. The EI declined as fruit ripening progressed and was not influenced by fruit size. Fruits harvested at the pre-natural fruit drop stage (pre-NFDS; 2 to 3 days before fruit drop) and the post-natural fruit drop stage (post-NFDS) were kept at 25 °C for 10 days. No significant differences were detected between fruits at these two stages in terms of the EI and flesh firmness, except that both variables at the pre-NFDS were higher than those at the post-NFDS after 0 and 4 days and after 0 day of storage, respectively. Similarly, no significant differences were found between fruits at these two stages in terms of total sugar and organic acid contents, regardless of the length of the storage period. Fruits harvested at pre-NFDS were individually wrapped in low-density polyethylene film (11 μm thick) and stored at 10, 15, 20, and 25 °C for 10 days. The EI of fruits kept at 10 °C was higher than that of fruits stored at 15 to 25 °C regardless of the presence of film wrapping. At 10 °C storage, the EI of film-wrapped fruits was higher than that of non-film-wrapped fruits. Film-wrapped fruits harvested at pre-NFDS were stored at 10 °C for 30 days. After 15 days in storage, relatively rapid and then gradual declines in both the EI and flesh firmness were observed. Sugar content was unaffected by the storage period, but organic acid content decreased after 30 days in storage. A strong positive correlation was found between the EI and flesh firmness. When the data set was limited to fruits less than 20 N·cm<jats:sup>−2</jats:sup> in flesh firmness and more than 350 g in weight, the correlation coefficient was higher compared with a data set with all fruit combined. The results of this study indicate that flesh firmness in ‘Irwin’ mangos can be estimated by measuring the EI. Moreover, the ripening stage, storage temperature, and film wrapping affected the retention of fruit quality.</jats:p>

Elasticity Index, Quality and Shelf-life of 16 Tree-ripe Mango Cultivars

“…Ongoing measurements of the same fruits showed that the EI for all cultivars rapidly declined over the first 2 days of storage, and thereafter decreased gradually over the following 8 days. Such declines in EI during fruit ripening have been reported for fruits such as pears (Murayama et al, 2006;Terasaki et al, 2006), kiwifruit (Terasaki et al, 2001), grape (Takahashi et al, 2010), and pitaya (Fumuro et al, 2013); in mango, they have previously been observed in 'Irwin' and 'Aikou' (Fumuro and Sakurai, 2014;Fumuro et al, 2015).…”

“…Changes in the EI and fruit quality over time during storage Fumuro and Sakurai (2014), and Fumuro et al (2015) reported positive correlations between EI and flesh firmness, and revealed the high utility of EI for estimating mango flesh firmness and conducting ongoing measurements on the same fruits. In addition, their experiments suggest that flesh firmness may be estimated from EI, regardless of mango cultivar.…”

“…To minimize weight loss and flesh softening, immediately after harvest, fruits were individually wrapped with polyethylene film (30 cm width, 11 µm thickness; Ube Film Co., Ltd., Sanyo-Onoda, Japan) (Fumuro and Sakurai, 2014), with a water vapor transmission rate of 10 g·m storage Changes in the second resonance frequency (SRF), weight, and peel color were determined after 0, 2, 4, 6, 8, and 10 days of storage. The SRF was measured using portable vibration measurement equipment (Vp-2; Seibutsu-Sindo-Kenkyusyo, Higashi-Hiroshima, Japan).…”

“…Recently, a nondestructive resonance method was developed allowing follow-up measurements to be made with high accuracy even in a small number of fruits . This new technique has been used to investigate the ripening of various fruits including pears (Murayama et al, 2006;Terasaki et al, 2006), kiwifruits (Muramatsu et al, 1997(Muramatsu et al, , 1999Terasaki et al, 2001), apples (Muramatsu et al, 1999), persimmons (Muramatsu et al, 1999;Taniwaki et al, 2009), nectarines (Muramatsu et al, 1996), pitayas (Fumuro et al, 2013), and mangoes (Fumuro and Sakurai, 2014;Fumuro et al, 2015).…”

“…However, because SRF declines as fruit weight increases, the elasticity index (EI), which is calculated using fruit weight and SRF and minimizes the effect of fruit weight, is used as an indicator of flesh firmness (Cooke, 1972;Terasaki et al, 2001). In addition, positive correlations between the EI, as determined by nondestructive resonance vibrations, and flesh firmness, as determined by destructive methods, were reported for several fruits, such as pears (Murayama et al, 2006), apples (Motomura et al, 2004), kiwifruits (Muramatsu et al, 1999;Terasaki et al, 2001), and mangoes (Fumuro and Sakurai, 2014;Fumuro et al, 2015).…”