Millions from Waste

by Frederick Arthur Ambrose Talbot

In the eyes of many people the addition of potato-flour to wheaten flour for bread may seem reprehensible, and to savour of adulteration. Prejudice is a wellnigh insuperable obstacle to overcome. But in this instance such opposition is misplaced. The introduction of farina to the loaf cannot be regarded as an adulterant, substitute, or even a diluent. Rightly or wrongly, the potato is invested with a high food value: in some quarters it is even held to be an equivalent to the wheat flour. Doubtless opposition would arise from memories of the practice which obtained during the early days of the war. But the faults which were encountered then were due to the method and not to any shortcomings upon the part of the ingredient.

The utilization of the potato for the production of bread is not even a modern innovation. It really represents a revival of a long-since abandoned and wellnigh forgotten art. In the early years of the Victorian era our bakers were compelled to make resort to the potato as a constituent of the loaf. The home-grown wheat physiologically was not adapted to the making of bread, and the same argument applies more or less to the domestically grown cereal of these days. Normally, only a certain volume can be used; it has to be blended with imported flour to obtain the requisite percentage of gluten in which the domestic cereal is deficient. The bakers of a century ago used the potato to obtain the gluten content. With the availability of the more glutinous imported flour recourse to the potato declined, until finally the practice was abandoned.

The revival of the principle to meet the conditions of war proved a failure from the simple fact that the baker had lost his cunning, and was neither so clean nor so painstaking as his forbears in regard to his utensils and the handling of the tuber. The potato is particularly sensitive to contamination. Should an imperfectly-cleaned utensil be used the resultant bread will speedily sour. Moreover, the mashing of the potato was carried out very indifferently, while its admixture with the other constituents was still more unsatisfactorily fulfilled, with the result that the loaf was a spongy, unattractive, unappetizing, and indigestible mass of doubtful nutritive value.

If the potato be used in the farinaceous form no such objections can be levelled against the ultimate bread. The ingredients can be blended more completely. It is this circumstance which renders the outlook for the potato-flour so promising, and the British process which has been perfected for its production should meet with far more gratifying success.

The preparation of the farina is simple and straightforward. The potatoes are taken in hand immediately after they have been dug, and so are perfectly fresh. They are emptied into hoppers to pass to the washing machine. Then they proceed to the steam-cooker where, unpeeled, they are partially cooked. Finally they are conveyed to the flaking machine, where the first stage of the process is completed. The potato is passed between closely-set, internally-heated rollers, the pulp being rolled out into a continuous sheet about as thick as tissue paper. During this stage the cooking process is completed, while the product is dried and converted into a crisp substance which is peeled from the final roller to fall in a shower of tiny flakes into a trough. It will be observed that the skin, eyes, and other deleterious portions, from which all flesh has fallen away, is collected with the main product.

Cooking, pulping, and flaking expels practically the whole of the 75 per cent. of water entering into the composition of the raw potato. The secret of the process is the control of the temperature, which must be maintained at a critical level, to assure the perfection of the product. If this be excessive there is the risk of the flake becoming charred, while, similarly, should the heat fall below the predetermined point, the product will lack dryness and crispness. As may be imagined, the treatment reduces the bulk of the potato very perceptibly, 5 tons of potatoes being required to furnish 1 ton of flake.

The second process is of the conventional milling character, the flake being ground to an extremely fine consistency. During this process the skin and all other inedible portions are removed. It may be mentioned that by turning the tubers into flake, slightly diseased potatoes, which would be useless for the table, or which could only be wastefully adapted to such a purpose, may be used without imperilling the purity of the product in any way, and with the minimum of loss. The flaking process presents an absolutely sterilized flour, the diseased portions being removed during milling.

All offal is carefully collected to be treated separately. It has pronounced food value for cattle, and, consequently, is converted into a meal. The production of 1 ton of farina yields about 300 lb. of offal, worth about £20—$100—a ton. The farina itself is of very fine consistency, yellowish-white in colour, appetizing in appearance, of pleasing aroma, the distinctive fragrance of the potato being scarcely discernible, and, if preserved from the damp, may be kept indefinitely.

It is not imperative that the flake should be milled immediately. In the former condition the potato may be safely stored in bags in a dry place after the manner of grain. It is not even essential to turn it into farina at all. In the flake form it constitutes an excellent base for the other industries to which it may be applied. It may be distilled for the extraction of the alcohol, excellent whisky, as is doubtless well known, being made from the potato, while large quantities of British brandies are produced from the starch which, by treatment with weak sulphuric acid, is converted into glucose, which is then fermented. Thus, it will be seen, the flake really represents the starting-point for numerous applications, each of which has its individual commercial possibilities. The outstanding advantage accruing from the conversion of the potato into flake is that it enables the product to be kept indefinitely, without suffering the slightest deterioration, and without any waste being incurred. I have seen samples which have been stored for seven years, and which to-day are in every way as good as flake fresh from the machine.

In setting forth the composition of the succulent tuber I referred to the item waste, which in the analysis given stands at 1.4 per cent. This is the ultimate residue from certain operations, but is not common to all, as, for instance, in the production of farina, where everything of a solid nature is utilized. But in some branches of industrial use there results a residue for which, at present, no attractive purpose has been found, although there are hopes that even this insignificant fraction will ultimately prove capable of profitable exploitation.