Stuart K. Johnson

Effect of fat replacement by inulin or lupin-kernel fibre on sausage patty acceptability, post-meal perceptions of satiety and food intake in men

The present study examined whether replacing fat with inulin or lupin-kernel fibre influenced palatability, perceptions of satiety, and food intake in thirty-three healthy men (mean age 52 years, BMI 27.4 kg/m(2)), using a within-subject design. On separate occasions, after fasting overnight, the participants consumed a breakfast consisting primarily of either a full-fat sausage patty (FFP) or a reduced-fat patty containing inulin (INP) or lupin-kernel fibre (LKP). Breakfast variants were alike in mass, protein and carbohydrate content; however the INP and LKP breakfasts were 36 and 37 % lower in fat and 15 and 17 % lower in energy density respectively compared with the FFP breakfast. The participants rated their satiety before breakfast then evaluated patty acceptability. Satiety was rated immediately after consuming the breakfast, then over the subsequent 4.5 h whilst fasting. Food consumed until the end of the following day was recorded. All patties were rated above neither acceptable or unacceptable, however the INP rated lower for general acceptability (P=0.039) and the LKP lower for flavour (P=0.023) than the FFP. The LKP breakfast rated more satiating than the INP (P=0.010) and FFP (P=0.016) breakfasts. Total fat intake was 18 g lower on the day of the INP (P=0.035) and 26 g lower on the day of the LKP breakfast (P=0.013) than the FFP breakfast day. Energy intake was lower (1521 kJ) only on the day of the INP breakfast (P=0.039). Both inulin and lupin-kernel fibre appear to have potential as fat replacers in meat products and for reducing fat and energy intake in men.

Phytoestrogens: End of a tale?

Phytoestrogens are plant‐derived hormone‐like diphenolic compounds of dietary origin that are present at high levels in plasma of subjects living in areas with low atherosclerosis and cancer incidence. The term phytoestrogen is commonly applied to the soy isoflavones genistein, daidzein and glycitein. As outlined in a previous review article in this journal by Adlercreutz and Mazur 1, these compounds are weakly estrogenic and appear to influence the cardiovascular system, the production, metabolism and biological activity of sex‐hormones, as well as malignant cell proliferation, differentiation and angiogenesis. Recently skepticism has developed concerning the true potential of phytoestrogens to beneficially modify these processes. A critical analysis of the early findings from supplementing the diet with soy protein has failed to confirm phytoestrogens as the responsible agent for beneficial cardiovascular effects, be it by way of lipid reduction, vasodilation or lipoprotein oxidation. Furthermore, contrasting data have been reported on the potential of phytoestrogens to prevent hormone‐dependent cancers (e.g. breast and prostate) and to successfully treat post‐menopausal complaints, an indication for which they are widely used. These potentially negative findings have led health authorities in several countries to suggest maximum daily intake levels for phytoestrogens. There is now growing interest in the use of soy products containing low levels of phytoestrogens and in research on other phytoestrogen free legumes such as lupin.

Lupin kernel fibre-enriched foods beneficially modify serum lipids in men

AbstractObjective:To examine the effect of a diet containing a novel legume food ingredient, Australian sweet lupin (Lupinus angustifolius) kernel fibre (LKFibre), compared to a control diet without the addition of LKFibre, on serum lipids in men.Design:Randomized crossover dietary intervention study.Setting:Melbourne, Australia — Free-living men.Subjects:A total of 38 healthy males between the ages of 24 and 64 y completed the intervention.Intervention:Subjects consumed an LKFibre and a control diet for 1 month each. Both diets had the same background menus with seven additional experimental foods that either contained LKFibre or did not. Depending on energy intake, the LKFibre diet was designed to contain an additional 17 to 30 g/day fibre beyond that of the control diet.Results:Compared to the control diet, the LKFibre diet reduced total cholesterol (TC) (mean±s.e.m.; 4.5±1.7%; P=0.001), low-density lipoprotein cholesterol (LDL-C) (5.4±2.2%; P=0.001), TC: high-density lipoprotein cholesterol (HDL-C) (3.0±2.0%; P=0.006) and LDL-C:HDL-C (3.8±2.6%; P=0.003). No effects on HDL-C, triacylglycerols, glucose or insulin were observed.Conclusions:Addition of LKFibre to the diet provided favourable changes to some serum lipid measures in men, which, combined with its high palatability, suggest this novel ingredient may be useful in the dietary reduction of coronary heart disease risk.Sponsorship:Grains Research and Development Corporation, Australian Research Council and the Department of Agriculture Western Australia.

Lupin kernel fibre foods improve bowel function and beneficially modify some putative faecal risk factors for colon cancer in men.

Consumption of some dietary fibres may benefit bowel health; however, the effect of Australian sweet lupin (Lupinus angustifolius) kernel fibre (LKFibre) is unknown. The present study examined the effect of a high-fibre diet containing LKFibre on bowel function and faecal putative risk factors for colon cancer compared to a control diet without LKFibre. Thirty-eight free-living, healthy men consumed an LKFibre and a control diet for 1 month each in a single-blind, randomized, crossover study. Depending on subject energy intake, the LKFibre diet was designed to provide 17-30 g/d fibre (in experimental foods) above that of the control diet. Bowel function self-perception, frequency of defecation, transit time, faecal output, pH and moisture, faecal levels of SCFA and ammonia, and faecal bacterial beta-glucuronidase activity were assessed. In comparison to the control diet, the LKFibre diet increased frequency of defecation by 0.13 events/d (P=0.047), increased faecal output by 21 % (P=0.020) and increased faecal moisture content by 1.6 % units (P=0.027), whilst decreasing transit time by 17 % (P=0.012) and decreasing faecal pH by 0.26 units (P<0.001). Faecal butyrate concentration was increased by 16 % (P=0.006), butyrate output was increased by 40 % (P=0.002) and beta-glucuronidase activity was lowered by 1.4 micromol/h per g wet faeces compared to the control diet (P<0.001). Addition of LKFibre to the diet incorporated into food products improved some markers of healthy bowel function and colon cancer risk in men.

Palatability and glucose, insulin and satiety responses of chickpea flour and extruded chickpea flour bread eaten as part of a breakfast.

Objective: To determine the effect of adding chickpea flour or extruded chickpea flour to white bread on palatability and postprandial glycaemia, insulinaemia and satiety.Design: A randomised, single-blind, cross-over study of four 50 g available carbohydrate breakfasts.Setting: School of Exercise and Nutrition Sciences, Deakin University.Subjects: In all, 12 healthy subjects were recruited through posted notices. Totally, 11 (nine male, two female) completed the study (mean±s.e.m.; age 32±2 y; body mass index, 24.7±0.8 kg/m2).Intervention: After overnight fasting, subjects consumed a control (white) bread (WB) breakfast twice, a chickpea bread (CHB) breakfast once and an extruded chickpea bread (EXB) breakfast once. Palatability and postprandial blood glucose, insulin and satiety responses were determined. Following this, food intakes from an ad libitum buffet and for the remainder of the day were assessed.Results: A trend towards a lower incremental area under the curve (IAUC) of glucose for the CHB breakfast compared to the WB breakfast was observed (P=0.087). The IAUC of insulin and insulinaemic index (II) of the CHB breakfast were higher (P<0.05) than for the WB breakfast. No differences in glycaemic index (GI), satiety response, food intake or palatability were observed.Conclusions: CHB and EXB demonstrated acceptable palatability. CHB demonstrated some hypoglycaemic effect compared to WB, but neither CHB nor EXB demonstrated effects on satiety or food intake. The hyperinsulinaemic effect of CHB observed in this study requires further investigation.Sponsorship: Grains Research and Development Corporation.

Protein quality and physico-functionality of Australian sweet lupin (Lupinus angustifolius cv. Gungurru) protein concentrates prepared by isoelectric precipitation or ultrafiltration

Abstract The protein quality and physico-functional properties of Australian sweet lupin protein concentrates, prepared by isoelectric precipitation or ultrafiltration, were assessed. The ultrafiltration process resulted in a higher yield of protein than did the isoelectric precipitation process. The lupin kernel and the two lupin protein concentrates had similar essential amino acid compositions that were inferior to ideal human requirements. True digestibilities of the isoelectrically precipitated (ISO) and the ultrafiltered (UF) lupin protein concentrates were similar but significantly higher (P

Water-binding capacity and viscosity of Australian sweet lupin kernel fibre under in vitro conditions simulating the human upper gastrointestinal tract

There is currently little understanding of the physicochemical properties in the human gastrointestinal tract of Australian sweet lupin (Lupinus angustifolius) kernel fibre (LKF), a novel food ingredient with potential for the fibre enrichment of foods such as baked goods. Since physicochemical properties of dietary fibres have been related to beneficial physiological effects in vivo, this study compared water-binding capacity and viscosity of LKF with that of other fibres currently used for fibre-enrichment of baked goods, under in vitro conditions simulating the human upper gastrointestinal tract. At between 8.47 and 11.07u2009g water/g dry solids, LKF exhibited water-binding capacities that were significantly higher (Pu200a<u200a0.05) than soy fibre, pea hull fibre, cellulose and wheat fibre at all of the simulated gastrointestinal stages examined. Similarly, viscosity of LKF was significantly higher (Pu200a<u200a0.05) than that of the other fibres at all simulated gastrointestinal stages. The relatively high water-binding capacity and viscosity of LKF identified in this study suggests that this novel fibre ingredient may elicit different and possibly more beneficial physiological effects in the upper human gastrointestinal tract than the conventional fibre ingredients currently used in fibre-enriched baked goods manufacture. We are now performing human studies to investigate the effect of LKF in the diet on health-related gastrointestinal events.

In vitro carbohydrate digestibility of whole-chickpea and chickpea bread products

Pulses such as the chickpea are generally considered to be valuable dietary sources of slowly digestible starch, a form of starch that is considered beneficial to health since it results in relatively low post-meal blood glucose levels compared with more rapidly digested starch. The development of novel chickpea-based foods is necessary to help expand the worldwide consumption of the chickpea. However, the effect of different processing methods on the starch digestibility of chickpea-based foods has not been widely investigated. This study used an in vitro method simulating human carbohydrate digestion to determine levels of slowly digestible starch, rapidly digestible starch (RDS), resistant starch, total starch and rapidly available glucose (RAG) of: (i) whole-chickpea products (domestically boiled, commercially canned and commercially precooked/vacuum-packaged); and (ii) standard white bread, chickpea flour bread (25% replacement of wheat flour by chickpea flour) and extruded chickpea flour bread (25% replacement of wheat flour by extruded chickpea flour). The RAG levels were then used to predict the relative in vivo glycaemic indices of the products. The commercially precooked/vacuum-packaged whole chickpeas demonstrated higher levels of RDS than the commercially canned and domestically boiled products (P<0.05). In addition, the domestically boiled product had lower levels of RAG (g/100 g available carbohydrate) compared with the canned and precooked/vacuum-packaged products (Pu200a<u200a0.05). There were no significant differences between any of the carbohydrate digestibility measures of the white bread, chickpea flour bread and extruded chickpea flour bread (Pu200a>u200a0.05) and all bread products demonstrated far higher RAG (g/100 g available carbohydrate) values than the whole-chickpea products. The findings suggest that the commercially precooked/vacuum-packaged whole chickpeas and the canned product may have higher and less beneficial glycaemic indices than the domestically boiled chickpeas. It appears unlikely that the use of chickpea flour or extruded chickpea flour, at the incorporation rate investigated in this study, would modify the glycaemic index of bread. It is probable, however, that the chickpea bread products investigated would demonstrate higher and potentially less beneficial glycaemic indices than the whole-chickpea products.

Lupin (Lupinus albus) protein isolate (L-ISO) has adequate nutritional value and reduces large intestinal weight in rats after restricted and ad libitum feeding.

Background: A protein isolate from white lupin (Lupinus albus; L-ISO) has potential as a novel human food ingredient, but its nutritional effects are unknown. Methods: We evaluated protein quality and effects on body composition in rats of isoenergic diets of L-ISO, lactalbumin, or casein with both restricted (10-day) and ad libitum (28-day)intake. The diets were equivalent in protein per se, but supplementation was used to balance essential amino acid levels. Results: In both studies, the rats consumed similar amounts of each diet, and no effect of diet on the gain:feed ratio was observed – though gain:N ratio and net protein utilization were slightly lower for the L-ISO diet. Lower large intestinal weights after the L-ISO than after the lactalbumin diet were observed in both studies. The L-ISO diet resulted in lowered body fat percentage in the 10-day study but in an elevated level in the 28-day study. Liver composition (DNA, RNA, glycogen, and fat) and plasma levels of some amino acids (His, Thr, Ala, Pro, Tyr, Val and Met) were affected by diet, but no effects on plasma lipid, glucose, or uric acid were observed. Conclusion: The L-ISO diet did not affect feed intake and has adequate nutritional quality in rats whilst modifying large intestinal weight in a potentially beneficial manner – suggesting potential for this protein in human nutrition.

Liking of health-functional foods containing lupin kernel fibre following repeated consumption in a dietary intervention setting☆

Liking of a particular food after repeated consumption may be reduced, limiting the effectiveness of health-functional foods requiring on-going consumption to deliver their benefits. This study examined the effect of repeated consumption of foods containing the novel ingredient, Australian sweet lupin (Lupinus angustifolius) kernel fibre (LKFibre) on sensory acceptability in the dietary intervention setting. In a single-blind randomised crossover 4-week intervention, participants consumed both control and equivalent LKFibre-containing products daily on separate interventions separated by a 4-week period on habitual diet. Seven products: muesli, bread, muffin, chocolate brownie, chocolate milk drink, pasta and instant mashed potato were assessed twice (days 4 and 18 of intervention), by 38 participants for appearance, texture, flavour and general acceptability using a structured graphic hedonic scale. Overall the results showed there was no reduction (P=0.594) in general acceptability of LKFibre foods after repeated consumption, suggesting potential for long-term consumption. The control food products were however generally preferred (P<0.001) over the LKFibre foods; the mean difference for general acceptability between being <6% (0.82cm) of the 15cm hedonic scale used, suggesting LKF addition did not severely affect product palatability.