#47 - Feb 2021 - Garden Stuff - © - Sandy Lang - slang@xtra.co.nz
WASTED FRUIT March: The Season of mists and mellow fruitfulness [Keats] and waste [Lang]... Fruit skin structure: Most fruit skins are thin (0.05 mm). Just one layer of small cells (epidermis) on top of about two layers of slightly larger cells (hypodermis). Inside this are the giant, thin-walled cells of the flesh (cortex). On top of the epidermis is a very thin (0.01 mm) waxy cuticle. Skin function: The fruit skin separates the watery, nutrient-rich insides from the dry outsides - overrun with pathogenic microbes trying to get in. Skin strength is determined by the epi- and hypodermal cells. Skin barrier properties are determined by the polymeric cuticle. An intact skin is an effective barrier. Stretch marks: But a fruit skin is easily damaged by browsing insects or by wind-rub (a nearby leaf). It’s also damaged if cuticle synthesis doesn’t keep up with skin-area growth. From flowering to harvest, a fruit’s insides grow to 64,000-times their initial volume and its skin extends to 2,000-times its initial area. To do this the flesh and skin cells divide many times over. Sometimes cuticle synthesis can’t keep up, so cuticular ‘microcracks’ occur when the cuticle is overstretched. The skin cells near a microcrack divide to form a corky layer (russet). This re-establishes the barrier - keeps water in, keeps microbes out. But we don’t like fruit with rough patches of brownish russet. Pollination: Pollination produces seeds - seeds produce hormones - hormones trigger growth. Poor pollination means few seeds – means small fruit – and crooked fruit (lopseeded=lopsided). We don’t like overlarge or oversmall or lopsided fruit. Ripeness: Trees flower over two or three weeks, so fruit are not all the same age, so they don’t all ripen at the same time. We don’t like underripe and overripe fruit. Damage: Birds peck, grubs burrow, pickers bruise. We don’t like damaged fruit. Market forces: On the tree, fruit are tatty – patchy, lopsided, too small, too big, too green, too yellow, pecked, bruised. But we like perfect fruit. So, retailers sell perfect fruit, so wholesalers sell perfect fruit, so cool-stores store perfect fruit, so packers pack perfect fruit (25% of all fruit entering a packhouse is below standard – some rejects go to local market, the rest are dumped). So, pickers pick perfect fruit (25% of all fruit is left in the orchard). We eat about 50% of the crop. About 50% is wasted…___________________________________
WASTED FRUIT March: The Season of mists and mellow fruitfulness [Keats] and waste [Lang]... Fruit skin structure: Most fruit skins are thin (0.05 mm). Just one layer of small cells (epidermis) on top of about two layers of slightly larger cells (hypodermis). Inside this are the giant, thin-walled cells of the flesh (cortex). On top of the epidermis is a very thin (0.01 mm) waxy cuticle. Skin function: The fruit skin separates the watery, nutrient-rich insides from the dry outsides - overrun with pathogenic microbes trying to get in. Skin strength is determined by the epi- and hypodermal cells. Skin barrier properties are determined by the polymeric cuticle. An intact skin is an effective barrier. Stretch marks: But a fruit skin is easily damaged by browsing insects or by wind-rub (a nearby leaf). It’s also damaged if cuticle synthesis doesn’t keep up with skin-area growth. From flowering to harvest, a fruit’s insides grow to 64,000-times their initial volume and its skin extends to 2,000-times its initial area. To do this the flesh and skin cells divide many times over. Sometimes cuticle synthesis can’t keep up, so cuticular ‘microcracks’ occur when the cuticle is overstretched. The skin cells near a microcrack divide to form a corky layer (russet). This re-establishes the barrier - keeps water in, keeps microbes out. But we don’t like fruit with rough patches of brownish russet. Pollination: Pollination produces seeds - seeds produce hormones - hormones trigger growth. Poor pollination means few seeds – means small fruit – and crooked fruit (lopseeded=lopsided). We don’t like overlarge or oversmall or lopsided fruit. Ripeness: Trees flower over two or three weeks, so fruit are not all the same age, so they don’t all ripen at the same time. We don’t like underripe and overripe fruit. Damage: Birds peck, grubs burrow, pickers bruise. We don’t like damaged fruit. Market forces: On the tree, fruit are tatty – patchy, lopsided, too small, too big, too green, too yellow, pecked, bruised. But we like perfect fruit. So, retailers sell perfect fruit, so wholesalers sell perfect fruit, so cool-stores store perfect fruit, so packers pack perfect fruit (25% of all fruit entering a packhouse is below standard – some rejects go to local market, the rest are dumped). So, pickers pick perfect fruit (25% of all fruit is left in the orchard). We eat about 50% of the crop. About 50% is wasted…___________________________________