CURING FRUIT.

New Zealand Herald, Volume LXVII, Issue 20607, 4 July 1930, Page 20

CURING FRUIT.

THE USE OF SULPHUR. When the preservation of fruit for winter use is being carried on tho simple process of curing by sulphuring is worth describing. The following is supplied by a well-known Californian authority:— After carefully cutting aitU spreading the ripe fruit with cut face up upon thoroughly clean trays, it is put into the sulphur house as quickly as possible. The trays are carefully stacked upon trucks, and some care should be taken to see that tho fumes can penetrate to all of tho fruit. When sulphur burns it. needs air; that is, the sulphur unites with the oxygen in the air to form a gas known as sulphur dioxide. This gas or so-called " sulphur fumes " is a good bleaching agent, as well as a good germicide. However, it is not very active upon dry materials, but in tho presence of moisture its action is much more rapid and effective. That is the reason for placing fruit in the sulphur house as soon after cutting as possible, or for sprinkling 1 lie fruit with \yatcr before bleaching. The sulphur dioxide is taken up by the moisture, or water, and becomes considerably more activo when in this form. This water solution of sulphur dioxide is sometimes called sulphurous acid. Without moisture tho gas from burning sulphur would have very little lasting effect upon tho fruit, but when water is present and the gas is dissolved, the sulphurous acid remains in the fruit for some time and gives a splendid preservative action.

Tho time of sulphuring varies a great deal, depending upon the kind and size of fruit, degree of ripeness, temperature and humidity of the air, etc. Most growers soon recognise tho proper appearance of the correctly-sulphured fruit, especially by noting tho amount of fruit syrup that has formed upon the surfaco duo to tho breaking of the fruit cells. Remember that it is an advantage if you can put tho fruit in the hot sunlight immediately after removing from tho sulphur house. Tho best results can bo obtained when the fruit is put out in the morning or early afternoon, in order to get tho longest possible period of hot sunlight immediately after sulphuring. After this initial drying is well under way it is advisable to stack* the trays and finish the curing moro slowly, it is a well-known fact that prolonged exposure to tho sun in very hot weather is apt to impair tho flavour of tho fruit and also mako it tough and stringy. All of tho above-outlined precautions arc so easily and simply carried out that the increased quality of tho bleached fruit will moro than pay for the added pains taken.