A method is reported for the measurement of non-starch polysaccharides (NSP) from plant foods. NSP are the major components of "dietary fibre."The polysaccharides are divided into cellulose and non-cellulosic material and the constituent sugars are determined by gasliquid chromatography.Starch is removed, after gelatinisation, by incubation with hog pancreatic a-amylase together with pullulanase. The enzyme preparations are shown to be specific for the hydrolysis of a-1,4-and a-l,6-glucosidic bonds, and not to affect NSP. The starch-free material is then analysed by three separate but complementary procedures : (A) hydrolysis with 1 M sulphuric acid after solubilisation of cellulose with 12 M sulphuric acid; (B) hydrolysis with 1 M sulphuric acid; and (C) extraction with phosphate buffer at pH 7 and 100 "C, solubilisation of cellulose with 12 M sulphuric acid and then hydrolysis with 1 M sulphuric acid. Neutral sugars are measured by gasliquid chromatography as alditol acetates and uronic acids by a colorimetric method. Starch made resistant to a-amylase digestion by food processing is identified by additional steps in procedure B, and measured as "resistant starch.'' Procedure A gives total NSP and procedure B neutral non-cellulosic polysaccharides. A value for cellulose is obtained as the difference between glucose measured in procedures A and B. Procedure C gives NSP insoluble in phosphate buffer a t pH 7. Soluble NSP is the difference between total NSP and insoluble NSP. Results for the NSP analysis of selected foods are given. Keywords: Non-starch polysaccharide determination ; gasliquid chromatography ; plant foods ; dietary jibre ; alditol acetates ENGLYST et al. : NON-STARCH POLYSACCHARIDES IN PLANT Analyst, VOZ. I07proved to be a valuable attempt to bring more precision to the determination of cell wall material in human food and has been used widely, including the UK food tables.20 However, it has been criticised because of incomplete removal of starch2f and the non-specific colorimetric methods used for the measurement of individual sugars.22Other methods for measuring dietary fibre have been described.23 Some set out to determine a fraction of food undigested in the human small intestine, but such an objective is an unsuitable basis for an analytical method. Other methods, such as those of Sloneker,24 Theander and Aman25 and Selvendran and Du Pont,12 are based on chemical separation and gasliquid chromatographic determination of individual sugars, and are more satisfactory.This paper describes a procedure for the isolation and measurement of non-starch polysaccharide in plant material, developed from that first described by Englyst,26 using gasliquid chromatography. The proposed procedure incorporates more effective and more specific enzyme preparations for the hydrolysis of starch and a more informative separation of non-starch polysaccharides. The problem of starch, made resistant to a-amylase digestion by food processing, being measured as NSP is overcome by a separate analysis. Experimental Appara...

SUMMARY An investigation was made of the effect of changing mean transit time (M1T) by administration of drugs which affect colonic motility on faecal microbial mass in man. Senokot was used to accelerate and codeine and/or loperamide to prolong transit in subjects maintained on a constant high fibre diet. Doses of Senokot or codeine/loperamide were adjusted to halve or double transit time measured during a three week control period on diet alone. Stools were collected throughout and analysed for bacterial mass by a gravimetric procedure. Transit was measured by a continuous marker method. Senokot decreased mean transit time from 63-9 to 25*0 hours (n=6), with increased stool weight from 148 to 285 g/day. Bacterial mass increased in all subjects from a mean of 16*5 to 20 3 g/day (dry weight) (p<0025). Codeine/loperamide increased mean transit time from 47 Ito 87 6 hours (n=5), with decreased stool weight from 182 to 119 g/day.

SUMMARY A new method is described for measuring the mean transit time (MTT) of digesta through the human gut in which a constant amount of marker (radio-opaque pellets) is fed to subjects with each meal over a period of weeks, and its excretion measured in the stools. The MTT measured by this method (MTT-C) has been compared with MTT measured by giving single doses of similar markers to the same subjects (MTT-S) and with the 800% transit time (80% TT). Mean values on three dietary regimes for the MTT-C (54 2 h + 2'5) and MTT-S (54-2 h + 2.6) were lower than that for 80 % TT (63 1 h + 3 0). The average MTT-C in a group of six healthy young men on an ad libitum diet was 2-3 days (range 0 7-4 0). When additional dietary fibre was added to a standard diet the average MTT-C fell (in all of five subjects) from 2-4 to 1 6 days. A continuous record of MTT-C is obtained by this new method which shows wide variations from week to week even on controlled dietary intakes. Using the single dose technique, evidence is produced which suggests that the MTT-S is a more accurate and reproducible method than the 80 % TT.The length of time that dietary residue remains in the colon is important in determining colonic metabolism. It is thought to be one of the factors which affects the occurrence of large bowel cancer (Burkitt, 1971) and may be relevant to the extent to which the gut microflora metabolize foreign organic compounds (Scheline, 1973) and dietary fibre (Southgate, 1973). It is also important in calculating the dose of radiation received from ingested radioactive material (Eve, 1966 Received for publication 4 December 1975 We have measured the mean transit time (MTT) of dietary residue through the gut by giving a constant number of radio-opaque pellets each day to healthy volunteers continuously over a number of weeks (MTT-C) and also by giving single doses of pellets (MTT-S) and recording the amount excreted daily in the stool. These data have been compared with that of the 80% transit time (80% TT) using the method of Hinton et al. (1969). The efficacy of these methods in detecting changes in transit due to diets high or low in dietary fibre has been observed. Methods SUBJECTSTwelve healthy male subjects aged from 22-32 years who were either medical students or members of staff took part in 23 studies. The protocol was fully explained to each subject and had been approved by the ethical committee of the Central Middlesex Hospital. MARKERSFor the continuous marker studies the marker used was radio-opaque barium sulphate impregnated polyethylene pellets (Portex Ltd.) which were approximately cube shaped, specific gravity 1 25, and mean weight 31 mg. They were treated with a 210 on 29 April 2019 by guest. Protected by copyright.

The effect on colonic function of adding wheat fiber for 3 weeks to the metabolically-controlled diets of six healthy volunteers has been studied. Increasing dietary fiber intake from 17 to 45 g/day increased fecal weight from 79 +/- 6.6 g/day to 228 +/- 29.9 g/day and shortened mean transit time, measured by a continuous marker method, from 57.8 +/- 8.3 hr to 40.3 +/- 8.9 hr. The increase in fecal weight was largely due to water. Fiber caused a dilution of fecal marker and an increase in fecal fat, nitrogen, and calcium output. Fecal sodium, potassium, and chloride showed only small changes but volatile fatty acid output increased significantly without concentrations changing. Fecal bile acid output increased from 199 +/- 46 mg/day to 279 +/- 46 mg/day. These changes are discussed in light of current views of the role of dietary fiber in protecting against colon cancer.

I . The effect of dietary fibre digestion in the human gut on its ability to alter bowel habit and impair mineral absorption has been investigated using the technique of metabolic balance.2 . Five healthy male students were studied for 9 weeks under controlled dietary conditions and during the last 6 weeks they took 36g pectin/d. Bowel habit, transit through the gut, faecal fibre excretion, calcium balance and faecal composition were measured. 3.During the control period only 15 % of the dietary fibre ingested was excreted in the stools and when pectin was added to the diet there was no increase in fibre excretion. Stool frequency and mean transit time were unchanged by pectin but stool wet weight increased by 33 % and faecal excretion increased (%) for fatty acids 80, nitrogen 47, total dry matter 28 and bile acids 35. Ca balance remained unchanged.4. It may be concluded from these results that dietary fibre is largely metabolized in the human gut and dietary pectin completely so. This could explain its lack of effect on bowel habit and Ca balance. Other changes in the faeces may be related to an increase in bacterial mass.