Nigel Lambert

Consumer acceptance of functional foods: issues for the future

In the past, it has been assumed that consumers would accept novel foods if there is a concrete and tangible consumer benefit associated with them, which implies that functional foods would quickly be accepted. However, there is evidence that individuals are likely to differ in the extent to which they are likely to buy products with particular functional properties. Various cross‐cultural and demographic differences in acceptance found in the literature are reviewed, as well as barriers to dietary change. In conclusion, it is argued that understanding consumers’ risk perceptions and concerns associated with processing technologies, emerging scientific innovations and their own health status may enable the development of information strategies that are relevant to wider groups of individuals in the population, and deliver real health benefits to people at risk of, or suffering from, major degenerative illnesses.

Development of a rapid dipstick immunoassay for the detection of peanut contamination of food

Polyclonal antisera were raised to conarachin, the 7S globulin of peanut, Arachis hypogea. The antisera were of high titre and were specific for conarachin, showing no significant cross‐reaction with proteins from a range of nuts and legumes, as determined by immunoblotting and ELISA. A dipstick ELISA was developed using these antisera as both the capture and detector elements of the assay. The final steps utilized an avidin‐biotin detection system and tetramethylbenzidine as the substrate. The dipstick assay was highly sensitive, and employed a simple one‐step extraction method. It was able to detect as little as 0.01% (w/w) of peanut in marzipan and 0.1% (w/w) of peanut in chocolate. Roasted nuts were also detected, down to a concentration of 0.1% (w/w) in both foods. The dipstick assay also functioned with a range of foodstuffs, and readily indicated any that contained peanut. This method enables analysts to test, for the first time, for the presence of peanuts in food in a fast and easy‐to‐use manner....

Reasons underpinning patients' preferences for various angina treatments

Objective  To elicit patients’ preferences for the treatment of angina.

A study of the trypsinolysis of pea 11 S globulin

Abstract The trypsinolysis of hexameric pea 11 S storage globulin (legumin) in high and low ionic strength conditions has been studied in relation to changes observed in subunit composition and quaternary/tertiary structure. Gel filtration, N-terminal analysis and SDS-PAGE revealed details on the probable method of enzyme attack. In high ionic strength a stable intermediate was formed, termed legumin-T. However, in low ionic strength, trypsinolysis proceeded further, completely degrading the tertiary/quaternary structure, with fragmentation to peptides. The site of initial enzyme attack was shown to be at the C-termini of the acidic polypeptides, eventually reducing their molecular mass to 33 000. The resulting hexameric legumin-T complex was shown by circular dichroism studies to possess a similar secondary structure of that of native legumin. The significance of 11 S globulin proteolysis to structure-function relationships in food systems and its relevance to nutritional value are discussed, together with the application of limited proteolysis for probing structural features of 11 S globulins and proteins in general.

Poor diet and smoking : the big killers : comparing health education in two hazard domains

Encouraging the UK public to quit smoking has been a public health feature for over a century to a greater or lesser degree. Persuading people to consume five or more portions of fruits and vegetables is a far newer health policy, with a history of only some ten years. The article compares the established anti‐smoking campaign with that of the fledgling “five‐a‐day” campaign to discover what, if anything, the latter can learn from the former, and what the future prospects may be for improving food choice. The two campaigns are compared in terms of the quality of health message and the environmental pressures adopted to facilitate the desired health behaviour. Motivation issues and the need to engage the public more were also seen as key campaign factors.

The use of anti-soya globulin antisera in investigating soya digestion in vivo

Polyclonal antisera have been developed which recognise the soya globulins glycinin and β-conglycinin. Their binding to proteolysed and processed globulins has been characterised with a view to using the antisera as probes to investigate the fate of soya globulins during digestion. Trypsinolysis reduced the immunoreactivity of β-conglycinin but increased that of glycinin by threefold, as determined by enzyme-linked immunosorbent assay (ELISA). However, both antisera recognised trypsinolysis products poorly by immunoblotting. These data are consistent with the fact that the anti-glycinin antiserum was raised to digested glycinin and would therefore recognise both intact and proteolytic intermediates of glycinin. The latter would be disrupted into component polypeptides by sodium dodecyl sulphate–polyacrylamide gel electrophoresis and hence would only be present in the ELISA and not after blotting. The antibody preparations were used to investigate the fate of soya globulins during in vivo digestion of a processed soya ingredient in rats. Both glycinin and β-conglycinin were digested rapidly, intact globulins disappearing from the gastrointestinal tract 3 h after dosing. Immunoreactive globulins were found in gut contents and associated with gut tissues but appeared to be in a semi-intact form, probably comprising proteolytic intermediates. This study demonstrates the usefulness of antibody methods in following the digestion of individual components in a complex mixture, such as is found in food. The availability of antibody preparations which recognise heat-stable epitopes will open the way for investigations into the effects of pre-treatments, such as cooking, which are pertinent to human consumption of legumes. © 2000 Society of Chemical Industry

Influence of fruit and vegetable extracts on lipid peroxidation in microsomes containing specific cytochrome P450s

Abstract We have examined the effect of 12 food extracts on iron/ascorbate-induced lipid peroxidation using microsomes enriched with specific cytochrome P450 isoenzymes, namely 1A1 and 3A4, prepared from human lymphoblastic cells. As a comparison, we also studied control microsomes, which contained negligible amounts of cytochrome P450. We observed antioxidant effects with both control and P450-containing microsomes in the case of grapefruit, green tea, coffee, tarragon and rosemary extracts. Pro-oxidant effects were observed for the brassica extracts (cabbage, cauliflower and Brussels sprouts) for all three microsome groups. Differences in the degree of lipid peroxidation between microsomes containing P450s 1 A 1 3 A 4 and control microsomes were seen for apple, tomato and parsnip peel extracts. The antioxidant properties of some of the food extracts were therefore modified by the presence of specific P450s. The results demonstrate the potential of P450-enriched microsomes in determining the antioxidant properties of food extracts and components.

Application of high-performance liquid chromatography to the assessment of subunit heterogeneity in plant 11S storage globulins

Plant 11S storage proteins from a wide range of species have been resolved into their component subunits by ion-exchange fast protein liquid chromatography under denaturing conditions. The complex profiles obtained were reproducible and characteristic for each plant species analysed. The technique is shown to have distinct advantages over the more conventional electrophoretic approaches used to assess 11S subunit heterogeneity. The potential for the fast protein liquid chromatographic method as a simple screening system is discussed.

A study of patient expectations in a Norfolk general practice.

Objective  To use semi‐structured interviews to ascertain patterns in patients’ expectations of health care and the extent to which these expectations were met or not.

Human cytochrome P450's are pro-oxidants in iron/ascorbate-initiated microsomal lipid peroxidation.

We have examined the effect of human cytochrome P450s (1A1,1A2,3A4,2A6,2B6,2D6,2E1) on ascorbate/iron-induced lipid peroxidation. Using microsomes prepared from human lymphoblastic cells enriched in recombinant cytochrome P450 isoenzymes, we have shown that the degree of peroxidation is a function of the amount of P450 present rather than the presence of any specific isoenzyme. Incorporated P450 increased the amount of peroxidation products by up to 2.1-fold compared to the control microsomes with no P450. It is therefore concluded that cytochrome P450s play a significant role in ascorbate/iron peroxidation.