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TRAGEDY OF THE BUDGET
879 ENZYME ACTIONS IN FOOD TECHNOLOGY
THE large-scale synthesis predicted; but it still seems
of foods has often been as remote as ever. If it should come about, and if the methods used are purely chemical, food production will be divorced from enzymology. Till then, the food technologist must be a versatile and well-informed enzyme chemist, for enzyme actions obtrude themselves in every sector of his craft. They control such processes as the developmental changes that bring seeds, fruits, or leaves into the conditions in which they are ready for harvest; the age-dependent changes in meat; maturation in such commodities as cheese and wine; and some of the changes that take place during storage. They will play an increasing part in the economical recovery of valuable components from material now discarded. Food technologists are not concerned with the more physiological actions of enzymes; but, by measuring the amount of an enzyme (or the product of its action) in foods, they can give valuable guidance to plant breeders. For instance, some varieties of mango contain 18 times as much ascorbic acid as others, and the shelf-life of many fruits depends on the stability of the pectin in them. Such differences depend on enzyme content, and enzyme assay could be used to
guide selection. 1,2 Food preservation is often regarded simply as a matter of preventing attack by bacteria and other organisms-hence the appeal of sterilisation by ionising radiations. This technique has so far proved disappointing, and it is well to remember that, even if sterility could be achieved without causing harmful side-reactions, the enzymes in many foods would remain active and would bring about changes that other methods of preservation control. Heating, if sufficiently prolonged, not only sterilises food but also inactivates most of the enzymes in it. Drying, the addition of acid, salt, or sugar, establishes conditions inimical to enzyme action. Most enzyme actions are slowed down by freezing, and oxidations or
obviously be prevented by excluding air. But are exceptions to all these generalisations. Some enzymes are remarkably thermostable, some continue to act even in the dry state, some are activated by freezing, and deterioration may be anaerobic. Deterioration during storage takes many forms: the development of off " flavours, the destruction of vitamins, the loss through respiration of the main substance of the food, and the formation of substances of varying degrees of toxicity. The actual nature of the changes that cause " off " flavours is not known. It is easy to show that this deterioration is accompanied by the accumulation of various volatile substances (acetaldehyde, for example) but no as yet identified substance is thought to be actually responsible for the change in flavour. Furthermore, this is a domain dominated by habit and opinion. Since most people agree that perfectly fresh green peas are ideal, cooks and food manufacturers take great pains to minimise enzyme actions by cooking peas soon after harvest and immediately after shelling. The processes used in the manufacture of tea are designed to promote actions similar to those that are so carefully avoided can
there
"
1. 2.
Aylward, F., Haisman, D. R. Czyhrinciw, N. ibid. p. 153.
Adv. Fd Res. 1969, 17, 1.
with peas.3 The enzyme actions that have gone on in the cheeses most relished by gourmets would, in any other protein food, be regarded as a deterioration. The enzymes responsible for these changes do not come from the milk: they are made by other organisms, and the amines produced in a ripe cheese are probably mildly toxic. The more acutely toxic products of deterioration (aflatoxin in a food that has been badly stored, for example) are also the product of the growth of other organisms. The only generalisation that can be hazarded is that changes brought about by a foodstuff’s intrinsic enzymes rarely, if ever, make it more toxic; sometimes they improve it and sometimes not. Enzyme actions brought about by even controlled invasion by other organisms are more suspect. Far-sighted scientists have for many years been grumbling about our wasteful habits and the pollution that they cause. The theme has suddenly caught public attention. The food industry is a crass offender. Fourfifths of the whey in the U.S.34 containing nearly 100,000 tons of protein a year, is wasted. When peas are harvested for quick freezing there is more protein in the discarded pods and vines than in the peas; and many other examples could be given. Byproducts are often used as fodder for ruminant and non-ruminant animals. Interest has recently been increasing in their use as substrates on which to grow bacteria or funguses that could be used as food or fodder. This is encouraging, but animal or microbial conversion is of necessity accompanied by losses that range from 60% to 95%, because of the converters’ own metabolic processes. One approach is to extract some at least of the- valuable constituents from a waste by mechanical means; more than half the protein in pea waste can be extracted. Selective enzymic destruction would be an alternative approach. Byproducts are sometimes discarded for purely xsthetic reasonsthe outer leaves of cabbages, for example. More often they are indigestible, either intrinsically (as in feathers) or because of the presence of more fibre than the human gut can tolerate. The aminoacids in feathers would become useful if the structure were dispersed by a keratinase; and useful protein, fat, and carbohydrate would be liberated if a cellulase were available that was substantially free from enzymes able to act on the useful components. Cellulose is the most abundant single organic substance: it is odd that so little attention is paid to the enzymes that act on it. TRAGEDY OF THE BUDGET
IN his third budget, Mr. Jenkins has gone for the Seventeen million tax refunds at the beginning of July are worth more, in electoral terms, than any number of speeches about the balance of payments. From a Chancellor who in the past has shown some sense of social priorities, however, this is a sadly disappointing budget, not for what it does but for what it fails to do. Raising the tax threshold is in itself a perfectly reasonable measure. Indeed-as Mr. Heath was quick to point out-as fast as the Chancellor takes the lower-paid worker out of the taxable-income range, wage increases bring him back votes.
3. 4.
Bokuchava, M. A., Skobeleva, N. I. ibid. p. 215. Ben-Gera, I., Kramer, A. ibid. p. 77.
880 in. It is to Mr. Jenkins’ credit that, both last year and this, he has managed to help those at the bottom of the taxpaying scale without giving a substantial bonus to the rich, by an ingenious combination of higher personal allowances and abolition of the 4s. and 6s. rates of tax. Inflation, left to itself, has the effect not only of bringing more people into the tax net, but also of increasing the tax liability of those already in. Mr. Jenkins’ strategy has been, broadly, to counteract the first of these effects while letting the second take its course. By a slightly different method, he has similarly raised the starting-point for surtax without giving anything to those in the higher ranges. Most of the benefit of these changes, however, will go to the groups who can hardly be regarded as most in need of relief. Of the 2 million people entirely freed from income tax, over11/2 million are single men and women or working wives. Thus a family in which the mother and two working children each bring in E8 a week, in addition to the father’s earnings, will benefit by between E70 and E90 a year. But a family in which the mother has to stay at home to care for two young children will get, at most, E27. The additional personal allowance for 100,000 divorced, separated, and unmarried mothers who do not qualify for it at present is a welcome reform. Yet even this will not benefit the neediest fatherless families-those whose incomes are already below the taxpaying level. The right way to help the poor is not through the tax system but through direct social benefits. The not budget speech is necessarily the right time to announce increases in benefits. Pensioners, after all, got their last increase only six months ago, and the poorest among them can at least expect another increase in supplementary benefits in the autumn, even if they have to wait until next year for a further rise in insurance benefits. For the poorest group of all, however-families of low-paid workers who cannot even claim supplementary benefit because the father is working-the budget is a tragedy. Even the Shadow Chancellor, Mr. lain MacLeod, has reluctantly come round to the view that higher family allowances are the only effective way of raising these families’ incomes in the short run. And the only way of raising family allowances to a really adequate level at a tolerable cost to the Exchequer is by the ineptly named system of " clawback ", used in 1968 to adjust tax allowances for children so that only families with below-average incomes gained on balance. The budget, therefore, was the right time to announce this change, which will now presumably have to wait for at least another year. Mr. Jenkins should have had the courage to do what he knows to be right. Political courage may lose votes, but so may political cowardice.
BACTERICIDAL SOAP To most people a " clean " smell is a whiff of chlorine or of some aromatic phenolic compound. Whether the many gallons of smelly disinfectant which are slopped around the public lavatories prevent any illness is a question no-one has yet answered satisfactorily, but most people seem to enjoy the subjective effects. The newer germicides, such as hexachloro-
phane, have no smell, so the washer knows that he is using a soap incorporating one of these compounds only by reading the print on the wrapper. In 1968 approximately half the toilet soaps sold in the U.S.A. contained a germicide of one sort or another, but the evidence that they had useful properties has been based mostly on small observations limited to particular aims, such as sterilising the surgeon’s hands. Their prophylactic use has never been seriously explored. The origin of many minor bacterial infections of the skin is obscure. Some arise from the entry of organisms at sites where the skin has suffered trivial damage, but some appear where there has been no obvious gap in the skin. Recurrent boils are often associated with nasal carriage of a staphylococcus of exceptional invasive power. The intact skin is, however, generally impenetrable to most bacteria and has considerable self-disinfecting properties. One factor in this defence, it has been suggested, is the natural staphylococcal flora. A bactericide might prevent exogenous infection-or it might encourage it by diminishing the natural flora. A large experiment with U.S. naval cadets tested the effects of bactericidal soaps over a long period under conditions not very different from those of normal domestic life.1 1330 midshipmen in a shore establishment were divided into port and starboard watches who, outside working hours and organised sport, lived separate lives. Over a period of six months one watch (602 men) used for all hygienic purposes a soap containing hexachlorophane and triclocarbon bought from commercial sources. The other watch (599 men) used a similar soap made by the same firm but containing no germicide. Both watches were instructed to throw away any soap they had, to avoid the use of all male toiletries during the trial, and to report any lesions of the skin or scalp to the sickbay. All the midshipmen were leading an active life in and out of doors, and minor damage to the skin was frequent. After six months the difference between the two watches was fairly obvious. The incidence of skin infections among those using the germicidal soap was 3-82% and among the others 6-84%. There was not much difference in the worse infections, such as boils, but overall the benefit of the germicidal soap was apparent. It did not cause any irritation or
photosensitivity. As a trial, the experiment was not entirely satisfactory. The two soaps were of different colours, so a participant knew whether he was sheep or goat. The bactericidal soap’s effect of decreasing body smell was apparent,
so
any close observer knew to which class
a
belonged. The midshipmen normally took three showerbaths a day and had clean linen daily-habits which might seem excessive but which are probably desirable in the humid summer of Chesapeake Bay. For those exposed to skin infections, the argument for routine protection of this sort is strong. Nevertheless, this trial would have been more informative if it had lasted longer. In Britain this kind of inquiry might come within the scope of the Royal College of General Practitioners. Minor infections of the skin are a serious matter for the housewife or the skilled fitter. man
1.
MacKenzie,
A. R.
J. Am. med. Ass. 1970, 211,
991.
THE large-scale synthesis predicted; but it still seems
of foods has often been as remote as ever. If it should come about, and if the methods used are purely chemical, food production will be divorced from enzymology. Till then, the food technologist must be a versatile and well-informed enzyme chemist, for enzyme actions obtrude themselves in every sector of his craft. They control such processes as the developmental changes that bring seeds, fruits, or leaves into the conditions in which they are ready for harvest; the age-dependent changes in meat; maturation in such commodities as cheese and wine; and some of the changes that take place during storage. They will play an increasing part in the economical recovery of valuable components from material now discarded. Food technologists are not concerned with the more physiological actions of enzymes; but, by measuring the amount of an enzyme (or the product of its action) in foods, they can give valuable guidance to plant breeders. For instance, some varieties of mango contain 18 times as much ascorbic acid as others, and the shelf-life of many fruits depends on the stability of the pectin in them. Such differences depend on enzyme content, and enzyme assay could be used to
guide selection. 1,2 Food preservation is often regarded simply as a matter of preventing attack by bacteria and other organisms-hence the appeal of sterilisation by ionising radiations. This technique has so far proved disappointing, and it is well to remember that, even if sterility could be achieved without causing harmful side-reactions, the enzymes in many foods would remain active and would bring about changes that other methods of preservation control. Heating, if sufficiently prolonged, not only sterilises food but also inactivates most of the enzymes in it. Drying, the addition of acid, salt, or sugar, establishes conditions inimical to enzyme action. Most enzyme actions are slowed down by freezing, and oxidations or
obviously be prevented by excluding air. But are exceptions to all these generalisations. Some enzymes are remarkably thermostable, some continue to act even in the dry state, some are activated by freezing, and deterioration may be anaerobic. Deterioration during storage takes many forms: the development of off " flavours, the destruction of vitamins, the loss through respiration of the main substance of the food, and the formation of substances of varying degrees of toxicity. The actual nature of the changes that cause " off " flavours is not known. It is easy to show that this deterioration is accompanied by the accumulation of various volatile substances (acetaldehyde, for example) but no as yet identified substance is thought to be actually responsible for the change in flavour. Furthermore, this is a domain dominated by habit and opinion. Since most people agree that perfectly fresh green peas are ideal, cooks and food manufacturers take great pains to minimise enzyme actions by cooking peas soon after harvest and immediately after shelling. The processes used in the manufacture of tea are designed to promote actions similar to those that are so carefully avoided can
there
"
1. 2.
Aylward, F., Haisman, D. R. Czyhrinciw, N. ibid. p. 153.
Adv. Fd Res. 1969, 17, 1.
with peas.3 The enzyme actions that have gone on in the cheeses most relished by gourmets would, in any other protein food, be regarded as a deterioration. The enzymes responsible for these changes do not come from the milk: they are made by other organisms, and the amines produced in a ripe cheese are probably mildly toxic. The more acutely toxic products of deterioration (aflatoxin in a food that has been badly stored, for example) are also the product of the growth of other organisms. The only generalisation that can be hazarded is that changes brought about by a foodstuff’s intrinsic enzymes rarely, if ever, make it more toxic; sometimes they improve it and sometimes not. Enzyme actions brought about by even controlled invasion by other organisms are more suspect. Far-sighted scientists have for many years been grumbling about our wasteful habits and the pollution that they cause. The theme has suddenly caught public attention. The food industry is a crass offender. Fourfifths of the whey in the U.S.34 containing nearly 100,000 tons of protein a year, is wasted. When peas are harvested for quick freezing there is more protein in the discarded pods and vines than in the peas; and many other examples could be given. Byproducts are often used as fodder for ruminant and non-ruminant animals. Interest has recently been increasing in their use as substrates on which to grow bacteria or funguses that could be used as food or fodder. This is encouraging, but animal or microbial conversion is of necessity accompanied by losses that range from 60% to 95%, because of the converters’ own metabolic processes. One approach is to extract some at least of the- valuable constituents from a waste by mechanical means; more than half the protein in pea waste can be extracted. Selective enzymic destruction would be an alternative approach. Byproducts are sometimes discarded for purely xsthetic reasonsthe outer leaves of cabbages, for example. More often they are indigestible, either intrinsically (as in feathers) or because of the presence of more fibre than the human gut can tolerate. The aminoacids in feathers would become useful if the structure were dispersed by a keratinase; and useful protein, fat, and carbohydrate would be liberated if a cellulase were available that was substantially free from enzymes able to act on the useful components. Cellulose is the most abundant single organic substance: it is odd that so little attention is paid to the enzymes that act on it. TRAGEDY OF THE BUDGET
IN his third budget, Mr. Jenkins has gone for the Seventeen million tax refunds at the beginning of July are worth more, in electoral terms, than any number of speeches about the balance of payments. From a Chancellor who in the past has shown some sense of social priorities, however, this is a sadly disappointing budget, not for what it does but for what it fails to do. Raising the tax threshold is in itself a perfectly reasonable measure. Indeed-as Mr. Heath was quick to point out-as fast as the Chancellor takes the lower-paid worker out of the taxable-income range, wage increases bring him back votes.
3. 4.
Bokuchava, M. A., Skobeleva, N. I. ibid. p. 215. Ben-Gera, I., Kramer, A. ibid. p. 77.
880 in. It is to Mr. Jenkins’ credit that, both last year and this, he has managed to help those at the bottom of the taxpaying scale without giving a substantial bonus to the rich, by an ingenious combination of higher personal allowances and abolition of the 4s. and 6s. rates of tax. Inflation, left to itself, has the effect not only of bringing more people into the tax net, but also of increasing the tax liability of those already in. Mr. Jenkins’ strategy has been, broadly, to counteract the first of these effects while letting the second take its course. By a slightly different method, he has similarly raised the starting-point for surtax without giving anything to those in the higher ranges. Most of the benefit of these changes, however, will go to the groups who can hardly be regarded as most in need of relief. Of the 2 million people entirely freed from income tax, over11/2 million are single men and women or working wives. Thus a family in which the mother and two working children each bring in E8 a week, in addition to the father’s earnings, will benefit by between E70 and E90 a year. But a family in which the mother has to stay at home to care for two young children will get, at most, E27. The additional personal allowance for 100,000 divorced, separated, and unmarried mothers who do not qualify for it at present is a welcome reform. Yet even this will not benefit the neediest fatherless families-those whose incomes are already below the taxpaying level. The right way to help the poor is not through the tax system but through direct social benefits. The not budget speech is necessarily the right time to announce increases in benefits. Pensioners, after all, got their last increase only six months ago, and the poorest among them can at least expect another increase in supplementary benefits in the autumn, even if they have to wait until next year for a further rise in insurance benefits. For the poorest group of all, however-families of low-paid workers who cannot even claim supplementary benefit because the father is working-the budget is a tragedy. Even the Shadow Chancellor, Mr. lain MacLeod, has reluctantly come round to the view that higher family allowances are the only effective way of raising these families’ incomes in the short run. And the only way of raising family allowances to a really adequate level at a tolerable cost to the Exchequer is by the ineptly named system of " clawback ", used in 1968 to adjust tax allowances for children so that only families with below-average incomes gained on balance. The budget, therefore, was the right time to announce this change, which will now presumably have to wait for at least another year. Mr. Jenkins should have had the courage to do what he knows to be right. Political courage may lose votes, but so may political cowardice.
BACTERICIDAL SOAP To most people a " clean " smell is a whiff of chlorine or of some aromatic phenolic compound. Whether the many gallons of smelly disinfectant which are slopped around the public lavatories prevent any illness is a question no-one has yet answered satisfactorily, but most people seem to enjoy the subjective effects. The newer germicides, such as hexachloro-
phane, have no smell, so the washer knows that he is using a soap incorporating one of these compounds only by reading the print on the wrapper. In 1968 approximately half the toilet soaps sold in the U.S.A. contained a germicide of one sort or another, but the evidence that they had useful properties has been based mostly on small observations limited to particular aims, such as sterilising the surgeon’s hands. Their prophylactic use has never been seriously explored. The origin of many minor bacterial infections of the skin is obscure. Some arise from the entry of organisms at sites where the skin has suffered trivial damage, but some appear where there has been no obvious gap in the skin. Recurrent boils are often associated with nasal carriage of a staphylococcus of exceptional invasive power. The intact skin is, however, generally impenetrable to most bacteria and has considerable self-disinfecting properties. One factor in this defence, it has been suggested, is the natural staphylococcal flora. A bactericide might prevent exogenous infection-or it might encourage it by diminishing the natural flora. A large experiment with U.S. naval cadets tested the effects of bactericidal soaps over a long period under conditions not very different from those of normal domestic life.1 1330 midshipmen in a shore establishment were divided into port and starboard watches who, outside working hours and organised sport, lived separate lives. Over a period of six months one watch (602 men) used for all hygienic purposes a soap containing hexachlorophane and triclocarbon bought from commercial sources. The other watch (599 men) used a similar soap made by the same firm but containing no germicide. Both watches were instructed to throw away any soap they had, to avoid the use of all male toiletries during the trial, and to report any lesions of the skin or scalp to the sickbay. All the midshipmen were leading an active life in and out of doors, and minor damage to the skin was frequent. After six months the difference between the two watches was fairly obvious. The incidence of skin infections among those using the germicidal soap was 3-82% and among the others 6-84%. There was not much difference in the worse infections, such as boils, but overall the benefit of the germicidal soap was apparent. It did not cause any irritation or
photosensitivity. As a trial, the experiment was not entirely satisfactory. The two soaps were of different colours, so a participant knew whether he was sheep or goat. The bactericidal soap’s effect of decreasing body smell was apparent,
so
any close observer knew to which class
a
belonged. The midshipmen normally took three showerbaths a day and had clean linen daily-habits which might seem excessive but which are probably desirable in the humid summer of Chesapeake Bay. For those exposed to skin infections, the argument for routine protection of this sort is strong. Nevertheless, this trial would have been more informative if it had lasted longer. In Britain this kind of inquiry might come within the scope of the Royal College of General Practitioners. Minor infections of the skin are a serious matter for the housewife or the skilled fitter. man
1.
MacKenzie,
A. R.
J. Am. med. Ass. 1970, 211,
991.