Grandma's Mango Magic: More Than Just Fortune? — Epoche B2
A crate of Alphonsos in Dadar The first mango crate of the season arrived at a flat in Dadar, Mumbai, this morning: four dozen Alphonsos, packed in straw, at about 1,100 rupees a dozen. The rule attached to that crate in this family was my grandmother's — that whoever ate the first properly ripe Alphonso of the year would have good fortune for the rest of it — and she either believed it or said she believed it, which I have come to think is a different thing and the most important thing in the story. What follows separates two questions that the rule keeps welded together. The first is why almost every practical instruction she attached to it was, as it turns out, technically correct: the six days of waiting, the refusal of the shiny uniform fruit, the insistence on going to Crawford Market in person because you cannot smell a photograph, the ability to tell Devgad fruit from Ratnagiri by the shape of the shoulder. The second is what the rule was doing, given that the fortune was never real. Nobody's year improved. Eleven people came to a flat in Dadar on a Sunday in May, ate too much aamras — mango pulp, pressed and sweetened, eaten with puri, the small fried breads — and stayed till evening, and they did it for thirty years without an invitation ever being sent. It is the absence of the invitation that needs explaining. Why the crate sits in straw for six days Mangoes are picked hard and green and ripen afterwards, which is not true of every fruit: a strawberry picked unripe stays unripe. Fruits divide into two classes on precisely this point. Non-climacteric fruits — strawberries, grapes, citrus — improve no further once cut from the plant. Climacteric fruits, of which the mango is one, respond to being picked with a sharp rise in respiration, the climacteric itself, and this rise is both triggered and sustained by a gas the fruit makes itself: ethylene, $\mathrm{C_2H_4}$, the plant hormone of ripening. The process is self-reinforcing, which is the key to the straw. Ethylene produced by one fruit induces neighbouring fruit to produce more of it, so ripening spreads and accelerates across a batch. Straw does two things to help. It slows the escape of the gas, so the concentration around the fruit builds instead of dispersing into the room; and it insulates, holding the crate closer to a steady warm temperature. Temperature matters because the reactions of ripening are ordinary chemistry, and their rate rises steeply with heat — Wills and Golding's postharvest handbook gives the working rule that respiration roughly doubles for each 10 °C rise. In a Mumbai April a crate on the floor of a flat is a warm, gas-tight, self-heating ripening chamber, and six days is what it takes. Underneath, starch is being broken down into sugars, pectins in the cell walls are being cut so the flesh softens, and green chlorophyll is degrading to reveal the carotenoid pigments that were there all along. Why she refused the shiny uniform ones The fruit she would not buy was the fruit that was already, improbably, the same colour all over. Her objection has a chemical basis and a legal one, and they are connected. The cheap way to force a crate is calcium carbide, $\mathrm{CaC_2}$, a grey solid that reacts with atmospheric moisture: $$\mathrm{CaC_2 + 2H_2O \to C_2H_2 + Ca(OH)_2}$$ The gas released is acetylene, $\mathrm{C_2H_2}$, which is structurally similar enough to ethylene to be recognised by the same machinery in the fruit — but only crudely. It sets off the colour change reliably and fast. It does not reproduce the rest of the sequence: the conversion of starch to sugar and the manufacture of aroma compounds run on their own slower schedule and are not brought forward to match. The result is a fruit that looks ripe and is not, uniformly coloured because the gas reached every part of the crate at once rather than because each fruit ripened at its own pace. Industrial-grade carbide carries a second problem, since it is typically contaminated with arsenic and phosphorus compounds that are released along with the acetylene. The letter says carbide ripening has been illegal in India for years, and it is worth putting a date on it: the prohibition is in the Food Safety and Standards (Prohibition and Restrictions on Sales) Regulations of 2011, made under the Food Safety and Standards Act of 2006, which forbid the sale of fruit artificially ripened with acetylene gas. Ripening with ethylene itself remains permitted under controlled conditions, which is the relevant distinction: the ban is not on hastening ripening but on the crude chemical shortcut that fakes its most visible symptom. Why you cannot smell a photograph Her refusal to order online rested on the same fact, stated from the buyer's side. Colour and aroma are on different clocks, and only one of them survives being photographed. A mango's smell comes from a mixture of volatile compounds — terpenes and lactones prominent among them — produced in quantity only in the last stage of ripening, after the skin has finished changing colour. Aroma is therefore the later and more reliable indicator, and it is the one that carbide cannot counterfeit, since the volatiles are made by pathways the gas does not accelerate. A photograph transmits exactly the property that can be faked and none of the property that cannot. Going to Crawford Market in person was not sentiment about markets; it was insistence on the only channel that carries the diagnostic signal. The shoulder She wanted Devgad fruit specifically, and could pick it out from the Ratnagiri boxes by the shape of the shoulder — the swell of the fruit around the stem end. Both are Alphonso, both are grown in the coastal Konkan strip of Maharashtra, and the origin is worth something: Alphonso from that region is protected as a geographical indication under India's Geographical Indications of Goods (Registration and Protection) Act of 1999, a scheme that reserves a name for produce from a defined place whose