Ascorbic Acid Effectively Improved Lutein Extraction Yield from Australian Sweet Lupin Flour

Lutein is a xanthophyll, a bioactive phytochemical that presents itself as colourful pigments in plants. Australian sweet lupin flour has been incorporated as a food ingredient in wheat bread and pasta to improve their sensory property and nutritional quality. However, the amount of lutein in lupin flour has not yet been determined. This is the first study to quantify naturally occurring lutein in Australian sweet lupin flour after the extraction efficiency was optimised. Several organic solvents (acetone, isopropyl alcohol, ethyl acetate and hexane), the use of an ultrasonic bath or a probe, the need for saponification and addition of ascorbic acid (served as antioxidant) were tested to compare the extraction yield. HPLC was employed to analyse lutein in flour. Lowest lutein (68 μg/100 g) was determined in the hexane extract. Samples extracted using an ultrasonic bath (126–132 μg/100 g) contained higher lutein than those extracted using a probe (84–109 μg/100 g). Saponified samples showed significantly less lutein (30–64 μg/100 g) than their respective non-saponified ones (122–134 μg/100 g). Without added ascorbic acid, lutein that was extracted into isopropyl alcohol was 143 μg/100 g and was higher than those released into acetone (92 μg/100 g). When ascorbic acid was added, measured lutein in the extracts of isopropyl alcohol (155 μg/100 g) and acetone (138 μg/100 g) increased by 8 and 33%, respectively. Our results suggested that the choice of extraction solvents and addition of ascorbic acid was crucial for quantitative analysis of lutein, so that the lutein content in lupin flour can be accurately reported

What is the cobalamin status among vegetarians and vegans in Australia?

Water-soluble vitamin B12 (cobalamin) plays a vital role in normal blood function and neurological functioning. Clinical and subclinical B12 deficiency has been notably reported in vegans, vegetarians, the elderly and metformin-treated diabetics. Currently, the prevalence of cobalamin deficiency among vegans and vegetarians in Australia is lacking; data on dietary intake including supplements and nutritional status are also limited. The increasing multiculturalism of Australia has seen an influx of imported foods, of which some may contain considerable vitamin B12. However, values for such foods are not included in the food composition databases. This review highlights the need to update the food composition database with culturally diverse foods containing vitamin B12. Moreover, the need for assessing dietary intakes and status using the most current best evidence and best practice on nutritional indicators (biochemical and functional biomarkers) to estimate the risk of deficiency and/or depletion is discussed

Determination of protein in lupin using liquid chromatography coupled with organic carbon detector and organic nitrogen detector (LC-OCD-OND): Validation of a new method

The Kjeldahl or Dumas methods used to estimate the crude protein in foods measure total organic nitrogen of foods. The limitation of these methods is that the estimated nitrogen is not solely derived from proteins. This is the first study to determine the protein content of Australian sweet lupin using size-exclusion chromatography interfaced with organic carbon detector and organic nitrogen detector (LC-OCD-OND), a method that is widely used in water research. Protein was initially extracted into 10 mM phosphate buffer saline, filtered and diluted prior to analysis. Measured protein in the lupin flour and the lupin protein isolate were 1.6 g and 6.1 g per 100 g, respectively, in agreement with results obtained from Bicinchoninic assay. The coefficients of variation for both intra and inter-variability studies were 5%. The work presented here introduces a fast and simple protein extraction from solid state prior to LC-OCD-OND analysis that specifically measures only soluble protein in lupins

Evaluating folate extraction from infant milk formulae and adult nutritionals: Enzymatic digestion versus enzyme-free heat treatment

© 2017 Elsevier Ltd This study compares enzymatic treatments to release folic acid (FA) and endogenous 5-methyltetrahydrofolate (5-MTHF) from infant milk formulae with enzyme-free heat extraction. The limits of detection and quantitation of FA were 1.4 ng/mL and 3.1 ng/mL, respectively; 7.5 ng/mL and 16.2 ng/mL for 5-MTHF. Absolute mean recoveries were 85% (FA) and 95% (5-MTHF). The RSD of the within-run variability was 6% and the inter-day variability was 8%. Averaged measurements of FA and 5-MTHF in SRM-1849a were within the certified value range. Analysed folate levels in three brands were greater than label values, because of inherently high 5-MTHF occurring in samples. The results indicate that enzyme-free heat treatment prior to UPLC–MS/MS analysis gives better sensitivity and reduces chromatographic interferences for the determination of FA and 5-MTHF in milk formulae than enzymatic treatments. Enzyme-free heat treatment is more compatible with UPLC–MS/MS than folate extraction techniques involving the addition of enzymes to milk