ANALYSES OF PLANT PRODUCTS IN GREATER DETAIL L. Paloheimo, K. A. Vainio, M.-L. Kero, and Eine Herkola Department of Animal Husbandry, University of Helsinki Received December 22, 1960 According to the customary Weende system food constituents are divided into 6 fractions: water, ash, crude fat, crude protein, crude fibre, and nitrogen free extract. This fractionation is, however, biologically very defective and even misleading (2, p. 16). Especially the dividing of the group of crude carbohydrates (N- and lipid- free organic matter) into crude fibre and N-free extract is quite unbiological; e.g. the main part of the lignin falls into the N-free extract together with starch and sugars. At this institute Paloheimo and Paloheimo (3, p. 1) have developed a method for a determination of the total of vegetable membrane subtances. When this frac- tion, together with the crude protein and crude fat, is subtracted from the organic matter, a fraction is obtained which we call valuable crude carbohydrates or simply valuable carbohydrates. This fraction contains besides starch, fructosans, and sugars, the main part of pectins. But it also contains some noncarbohydrate substances such as vegetable acids. We have further tried to fractionate the group of membrane substances deter- mining cellulose, lignin and pentosans. The sum of the percentages of these sub- stances is. however, usually somewhat smaller than the percentage of the mem- brane substances and thus we have had to enclose another fraction: other mem- brane substances. For the purpose of characterizing the quality of the investigated materials also in the conventional way, the crude fibre has been determined. Methods 1. The drying of the materals. The materials are dried in a vacuum oven at 70° C. 2. As h. Incineration at 700° C. 3. Crude protein. Nitrogen determination according to Kjeldahl. Crude protein factor 6.25. 4. Crude fat. The sample is shaken with water in room teperature, filtered, dried, and extracted with benzene-ethanol. https://www.c-info.fi/en/info/?token=xda8IVReBEoTdhrp.keoyyu8YgCxvWyz06vaRnQ.pQb21SEgiHjn2ROZkWjTCZoP_67N8TEBh0l-Rntm6xokY9OB8XrVTSPRgO_MuagZ4gXLCUbPyVfVX1N9ZNJUtiLwQhJd9FfRDnEMWEJL2bZ1-cDzqDaJ_eufEADtq6KNAED7mcIIW6nGetQTrhpi0_bisc2RRdevF9UkQp0_3tTrkOedGs-C2EB45UrOilDZE9o9-BHB2tMSqmseSABM3PKBGvFSYw 52 5. Membrane substances. According to the method ofPaloheimo and Paloheimo (l.c). The main principle of the method is boiling the sample with 0.05 normal hydrochloric acid. 6. The valuable crude carbohydrates. The percentages of crude fat, crude protein, and membrane substances are subtracted from the per- centage of the organic matter. 7. Cellulose. The method used will be described in detail in the near future. The main principle: shaking the sample with 3 normal NaOH solution in closed bottles in a boiling water bath. Corrections for pentosans and crude lignin. 8. Pentosans. For this determination the residue obtained the boiling of the sample in 0.05 normal HCI solution is used (see paragraph 5). The determina- tion is made according to the Tollens principle. Modification according to the Of- ficial Methods of Analysis (p. 376). 9. Lignin. The method used has been described by Salo (4, p. 187). Prehydrolysis is used; the main hydrolysis by 72 pet. H2S04; protein correction. 10. Other membrane substances. The percentages of cellulose, pentosans, and lignin are subtracted from the percentage of the membrane sub- stances. Results and discussion The results obtained by the above mentioned s}’stem of analysis are shown in Table 1. In Table 2 we have calculated for some of the materials the composition of the fraction »membrane substances» as percentages of this fraction. As the ash obtained by incineration is not a natural plant component and as it contains oxides and carbonates it is obvious that the unavoidable incorrectness of the ash determination results in figures too low for the valuable carbohydrates. The crude fat contains some nitrogen. This fragment of N multiplied by 6.25 will erroneously raise the crude protein percentage. The conventional protein factor is too low in cases where the protein contains bigger prosthetic groups poor in nitrogen. The omitting of these fragments, i.e. the prosthetic groups, in the crude protein determination, increases the figures of valuable carbohydrates, which however, results in a more correct conception of the nutritional nature of the material in question. Although theacid solution used in the determinationof the membrane substance fraction is greatly diluted, some of the cell wall constituents are dissolved and will thus be incorporated with the fraction of valuable carbohydrates. It is, however, possible that these easily hydrolysable carbohydrates may be digested even in the alimentary canal of animals with a simple digestive tract. This concerns especially the pectins which, according to our investigations, dissolve by the 0.05 normal acid. Thus the fact that the most readily hydrolysable cell wall constituents will be incorporated with the valuable carbohydrates may not seriously affect the method used. As one part of the valuable carbohydrates is an extract of the cell walls it is questionable if the term membrane substances is a proper name for the fraction obtained by boiling in 0.05 normal acid. Perhaps »fibre substances» would be a more Table 1. The composition of some vegetable materials. (Per cent of dry matter). _i fi S «Art— d .S U.OJS 4> 1. Spruce wood (Picea excelsa) 0.2 17 0.3 92.2 6.6 54.9 10.9 23.4 3.0 76.0 2. Pine » (Pinus sylvestris) 0.2 6.6 0.2 88.2 6.8 46.2 11.7 25.0 5.3 70.4 3. Birch » (Hetula verrucosa) 0.2 1.9 0.6 91.6 5.7 42.3 23.2 123 13.8 63.2 4. Rye, leaf stage 8.5 7.8 20.5 24.1 39.1 110 4.1 1.4 7.6 15.2 5. » before blooming 6.5 5.1 10.8 56.5 21.1 23.8 17.2 6.2 9.3 32.9 6. » blooming 5.0 4.6 7.7 63.8 18 9 28.3 19.1 8.5 7.9 38.5 7. » straw 6.0 4.0 2.8 79.1 8.1 34.7 23.0 12.5 8.9 47.5 8. Timothy, leaf stage 6.9 7.6 20.0 30.9 34.7 14.0 6.9 2.2 7.8 18.3 9. » before blooming 6.3 5.3 11.3 51.2 25.9 23.2 15.0 5.0 8.0 30.3 10. » blooming 5.6 4.4 8.6 56.2 25.2 26.6 16.7 7 1 5.8 35.2 11. » straw 4.9 3.4 4 4 61.3 26.0 28.2 18.7 9.9 4.5 37.4 12. Red clover, quite young 10.6 10.4 28.0 18.0 33.0 8.5 2.5 2.6 4.5 11.3 13. » » in bud 6.! 7.6 17.6 29.7 39.0 14.9 5.5 4.5 4.8 22.4 14. » » leaves 8.6 10.9 28.7 16.6 35.3 6.0 3.1 2.3 5.2 11.2 15. » » heads 6.4 6.4 20.0 29.5 37.7 12.8 4.3 9.6 2.9 21.6 16. » » stalks, upperhalves 6.9 4.9 8.9 59.8 20.5 26.8 12.2 10.2 10.6 42.2 17. » » »> lower » 5.3 4.9 7.8 64.5 17.5 28.5 11.5 10.7 13.8 47.8 18. Cocksfoot, pasture stage 9.5 7.6 21.4 28.8 32.8 17.7 6.8 3.2 1.1 20.3 19. Luzern, aftermath 10.1 6.2 22.4 35.0 26.3 17.3 7.4 6.4 3.9 28.2 20. Sedge (Carex gracilis) 6.1 5.7 17.5 60.2 20.6 190 13.8 6.9 10.5 24.1 21. Horsetail (Equisctum limosum) 15.8 4.8 11.0 40.9 27.5 24.4 4.1 3.7 8.7 24.7 22. Rush (Scirpus lacustcr) 7.8 4.6 10.3 63.6 23.7 26.1 12.4 6.1 9.0 31.3 23. Rush, marrow 8.2 2.7 4.9 39.2 46.0 22.3 8.5 2.6 5.9 24. Chickweed (Stellana media) 21.0 7.9 27.0 17.3 26.8 9.2 3.3 1.9 2.9 12.6 25. Birch leaves (Betula verrucosa) 3.9 12.1 19.8 23 5 40.7 9.0 4.3 11.3 -1.1 15.6 26. Alder leaves (Alnus incana) 4.3 9.6 26.2 15.9 44.1 8.3 2.4 6.3 -1.1 12.8 27. Aspen leaves (Populus tremula) 4.3 9.4 18.7 24.6 43 0 10.2 3.9 8.2 2.3 18.3 28. Dryopteris linnaeana, leaves 7.6 10.7 20.1 22.8 38.8 13.2 3.1 12.2 —5.7 15.6 29. Pteris; aquilina stalks 7.6 3.0 3.5 74.1 11.9 33.9 11.9 20.9 7.4 59.2 30. » » stalk rind 1.8 1.6 1.6 890 6.1 38.9 16.1 28.0 6.0 75.9 31. » » vascular bundles 1.7 5.7 81.6