260 



THE AC4PJCULTUEAL NEWS. 



August 15. 19H. 



FRUIT PRODUCTS. 



THE QUALITY OF COFFEE. 



The following ab.stract taken from the Experi- 

 ment Station Record for Janiuuy (1914) is interesting 

 because it demonstrates the fact that the quality of 

 agricultural produce, as far as the consumer is con- 

 cerned, does not rest entirely with the grower nor even 

 Avith the manufacturer. As regards the case in point — 

 the quality of cotiee — it will be seen that it is possible 

 for the consumer to form an eiToneou.s estimation of the 

 initial quality of this pnjduce simply through its prepar- 

 ation for consumption. 



This paper, read liefore the convention of the Xatioiial 

 Coifee Koa-sters' Association, November 191-3, discusses the 

 general .subject of coffee brewing with special reference 

 to the results of the analy.sis of coffee infusions prepared 

 by different methods. 



Stress is laid on the importance of fresh granulation and 

 accurate methods of measuring materials and temperatures. 

 A nuxture of Bogota and Santos coffee, medium roast, in 

 both medium ground and pulverized form, was used in the 

 experiments. Seven taldespoonfuls of coffee (SO gm. of 

 medium and 82 gm. of pulverized coffee) were used to six 

 cups of water (7-50 cc. ), which is the usual household allow- 

 ance. The coffee was prepared in four different ways, namely, 

 boiling, steeping, percolating, and filtration. 



Boiled coffee was made ' by placing medium ground 

 material in cold water, heating it to the boiling point at 

 which it was maintained for five minutes, and then adding 

 a little cold water to cause the grounds to settle. Steeped 

 coffee was made in the same way, except that it was settled 

 and poured off" directly the boiling point -svas reached. Finely 

 ground coffee was used for the percolated preparations and 

 the directions provided by the manufacturers of the perco- 

 lators were followed. Filtered coffee was prepared from 

 finely jjowdered coffee berries enclosed in a muslin l>ag over 

 which vigorously boiling water was poured. 



The amounts of total solids, tannin, and caff'ein in coffee 

 by each method were carefully deternuned. It was found 

 that the general strength of the brew (amount of total soliils 

 present) depended rather on the tinene.ss of granulation than 

 on the length of time which the coffee and water were cooked 

 together. Lengthening the cooking period (as in boiling or 

 percolating) tended to extract more tannin in proportion to 

 caffein and other bodies on which the desirable ttavotir seems 

 to depend. In percolators, water .far below the boiling point 

 in temperature is sprayed for a considerable period over .the 

 coffee, with the result that the flavour is not well extracted 

 though the tannin is, a fact, according to the author, contrary 

 to the claims of many manufatsturers. On the whole, filtra- 

 tion was found to produce coffee giving best results as regards 

 both ttavoiu' and low taiinin content. 



The amounts of tannin found in a cup of the various 

 infusions were as follows: boiled, 2'41 grains; steeped, 2"40 

 grains; percolated, 2'21 to 2'90 grains; filtered 0'20 to 0"25 

 grain. The amounts of caffein are: boiled, 2-50 grains; 

 .steeped (medium ground), 0'75 grain; steeped (finely ground), 

 1'7.5 grains; percolated, 2'75 grains; filtered, 2-.50 grains. 



factors in the deterioration ofi)id copi'a. Apart from 

 these itndersirable changes, lipase plays a useful part 

 in the germination of oil seeds. The presence iif the 

 enzyme in the seed of the coco-nut has for some time 

 been a matter of dispute, for although it was stated by 

 Dtitch and German workers in the East to occur in the 

 germinating seed, Walker of the Philippine Bureau of 

 Science failed to establish its presence. The discovery 

 of new methods ha.s led the Philippine workers to 

 repeat their investigation, and according to a paper in 

 the Philijipine Agriculturist and Forester {Xn]. Ill 

 N(j. 2), this has led to an agreement that the enzyme 

 is present in the crjco-nut. The following is a summary 

 of the results obtained: — 



(1) Lipase is present in the gerniinnting coco-iuit, both 

 as an enzyme and as a zymogen, which can be activated by 

 dilute acids. 



(2) It is found mainly in the outer part of the foot, or 

 haustorium; smaller amounts occur in the water nf the coco- 

 nut and the inner surface of the endosperm. 



(.3) Potassium cyanide and sodium arseuite, when used 

 in a concentration of 0'4 per cent., stop the action of the 

 enzyme. 



(4) Thymol can be used in as high a concentration as 

 -5 per cent, without any noticeable effect on the action oi the 

 enzyme. 



(■5) Boiling weakens but does not destroy the enzyme. 



(6) Coco-nut lipase works best in the condition created 

 by tlie addition of magnesium oxide: that is, in a practically 

 neutral niediuni. 



(7) Attention is called to the use of magnesitim oxide in 

 the study of lipa.se, as constituting a valualde improvement 

 over former methods of investigation. 



LIPASE IN THE COCO-NUT. 



The enzyme known as lipase is a substance which 

 causes fats to become rancifl. Lipase is thus tlie direct 

 cause of i-ancidity of butter and lard and is one of the 



THE RIPENING COCO-NUT. 



A paper dealing with the changes occurring during 

 the ripening of the coco-nttt apjjears in the Philippine 

 Agriculturist and Forester, (Vol. Ill, No. 2). In thi.s, 

 changes in size, weight and colour of the nut, and the 

 chemical changes in the milk and solid endosperm, are 

 dealt with principalh'. The ripening of the coco-nut is 

 diviiled int<j three periods : — 



During the first period there is an accumulation of invert 

 sugar and amino-acids in the milk or watery portion. The 

 meat is still absent, the shell and linsk are soft and watery, 

 and the nut as a whole has its greatest diameter along the 

 main axis. 



During the second period of growth, sucrose appears in 

 the milk, and the specific gravity of the latter is high. During 

 all this time water is lost from the coco-nut, though its total 

 weight continues to increase. The nut has meantime changed 

 its shape, and begins to accpiire its greate.st diameter in 

 a direction at right angles to the main axis. 



Dtiring the closing period of ripening, there is a sudden 

 rise in the content of oil in the endosperm. The specific 

 gravity of the milk falls at the same time, owing to the 

 transfer of nutrient materials or to respiration. In the mean- 

 time, the shell has become impervious, anil the drying out of 

 the husk results in a, lo.ss in weight, whicdi overbalances the 

 gain in weight dtie to other changes. 



The coco-nuts on which this work was undertaken are in 

 no way representative of really good nuts. The soil on which 

 they grow is shallow, and the ti'ees are poor individuals. The 

 analyses are therefore not expected to ))e representative of 

 average coco-nuts. 



