Dimitrios Zabaras

Binding of polyphenols to plant cell wall analogues - Part 2: Phenolic acids

Bacterial cellulose and cellulose-pectin composites were used as well-defined model plant cell wall (PCW) systems to study the interaction between phenolic acids (PA) derived from purple carrot juice concentrate (PCJC) and PCW components. Significant PA depletion from solution occurred, with pure cellulose initially (30s-1h) absorbing more than cellulose-pectin composites in the first hour (ca 20% cf 10-15%), but with all composites absorbing similar levels (ca 30%) after several days. Individual PAs bound to different relative extents with caffeic acid>chlorogenic acid>ferulic acid. Extrapolation of data for these model systems to carrot puree suggests that nutritionally-significant amounts of PAs could bind to cell walls, potentially restricting bioavailability in the small intestine and, as a consequence, delivering PAs to the large intestine for fermentation and metabolism by gut bacteria.

Acceptance of health-promoting Brassica vegetables: the influence of taste perception, information and attitudes

OBJECTIVE To investigate the relative importance of specific health knowledge and taste on acceptance of Brassica vegetables (broccoli, red and green cabbages, broccolini, cauliflower, Brussels sprouts). DESIGN In a sample of adults all reporting medium-high physical activity (as a marker/control of health behaviour) and reporting either low (≤2 portions/d) or high (≥3 portions/d) vegetable intake, half of those with low vegetable consumption (Li group) and half of those with high vegetable consumption (Hi group) received cancer protection information, while the other half did not (Ln and Hn groups), before hedonic (9-point), perceived taste and flavour impact responses (100 mm scales) to samples of six Brassica vegetables were elicited. Additionally, attitudes towards foods for health, pleasure and reward, sociodemographics, intentions to consume the vegetables in the near future and recall of health information were also measured. SUBJECTS Adult males and females (n 200) aged 18-55 years. SETTING Central location testing, Adelaide, Australia. RESULTS Information groups Li and Hi reported specific cancer protection information knowledge, in contrast to Ln and Hn groups (P < 0·000). Information independently influenced responses to (the least liked) Brussels sprouts only. Multivariate regression analysis found sensory perception tended to predict liking and intentions to consume Brassica vegetables. For example, broccoli hedonics (adjusted R 2 = 0·37) were predicted (P < 0·05) by bitterness (β = -0·38), flavour (β = 0·31), sweetness (β = 0·17) and female gender (β = 0·19) and intentions to consume (adjusted R 2 = 0·20) were predicted (P < 0·05) by bitterness (β = -0·38), flavour (β = 0·24), female gender (β = 0·20) and vegetable intake (β = 0·14). CONCLUSIONS Addressing taste dimensions (while retaining healthy compounds) may be more important than promoting health information in order to increase the popularity of Brassica vegetables.

Vitamin D2-Enriched Button Mushroom (Agaricus bisporus) Improves Memory in Both Wild Type and APPswe/PS1dE9 Transgenic Mice

Vitamin D deficiency is widespread, affecting over 30% of adult Australians, and increasing up to 80% for at-risk groups including the elderly (age>65). The role for Vitamin D in development of the central nervous system is supported by the association between Vitamin D deficiency and incidence of neurological and psychiatric disorders including Alzheimer’s disease (AD). A reported positive relationship between Vitamin D status and cognitive performance suggests that restoring Vitamin D status might provide a cognitive benefit to those with Vitamin D deficiency. Mushrooms are a rich source of ergosterol, which can be converted to Vitamin D2 by treatment with UV light, presenting a new and convenient dietary source of Vitamin D2. We hypothesised that Vitamin D2-enriched mushrooms (VDM) could prevent the cognitive and pathological abnormalities associated with dementia. Two month old wild type (B6C3) and AD transgenic (APPSwe/PS1dE9) mice were fed a diet either deficient in Vitamin D2 or a diet which was supplemented with VDM, containing 1±0.2 µg/kg (∼54 IU/kg) vitamin D2, for 7 months. Effects of the dietary intervention on memory were assessed pre- and post-feeding. Brain sections were evaluated for amyloid β (Aβ) plaque loads and inflammation biomarkers using immuno-histochemical methods. Plasma vitamin D metabolites, Aβ40, Aβ42, calcium, protein and cholesterol were measured using biochemical assays. Compared with mice on the control diet, VDM-fed wild type and AD transgenic mice displayed improved learning and memory, had significantly reduced amyloid plaque load and glial fibrillary acidic protein, and elevated interleukin-10 in the brain. The results suggest that VDM might provide a dietary source of Vitamin D2 and other bioactives for preventing memory-impairment in dementia. This study supports the need for a randomised clinical trial to determine whether or not VDM consumption can benefit cognitive performance in the wider population.

Anti-inflammatory effects of five commercially available mushroom species determined in lipopolysaccharide and interferon-γ activated murine macrophages

Inflammation is a well-known contributing factor to many age-related chronic diseases. One of the possible strategies to suppress inflammation is the employment of functional foods with anti-inflammatory properties. Edible mushrooms are attracting more and more attention as functional foods since they are rich in bioactive compounds, but their anti-inflammatory properties and the effect of food processing steps on this activity has not been systematically investigated. In the present study, White Button and Honey Brown (both Agaricus bisporus), Shiitake (Lentinus edodes), Enoki (Flammulina velutipes) and Oyster mushroom (Pleurotus ostreatus) preparations were tested for their anti-inflammatory activity in lipopolysaccharide (LPS) and interferon-γ (IFN-γ) activated murine RAW 264.7 macrophages. Potent anti-inflammatory activity (IC₅₀<0.1 mg/ml), measured as inhibition of NO production, could be detected in all raw mushroom preparations, but only raw Oyster (IC₅₀=0.035 mg/ml), Shiitake (IC₅₀=0.047 mg/ml) and Enoki mushrooms (IC₅₀=0.099 mg/ml) showed also potent inhibition of TNF-α production. When the anti-inflammatory activity was followed through two food-processing steps, which involved ultrasonication and heating, a significant portion of the anti-inflammatory activity was lost suggesting that the anti-inflammatory compounds might be susceptible to heating or prone to evaporation.

High-anthocyanin strawberries through cultivar selection

BACKGROUND Diets high in fruit and vegetables are known to have significant health benefits. This is in part due to the presence of phytochemicals, which possess potential protective health benefits. This study focuses on the ability of strawberries to be bred for higher anthocyanin content. This is a major contributor to the characteristic colour and nutritional value of ripe strawberries, together with phenolic acids, ascorbic acid and total antioxidant capacity. RESULTS Anthocyanins in five commercial strawberry cultivars and three breeding lines were assessed. This led to the discovery of one breeding line (BL 2006-221) as an exceptional source of anthocyanins (~1 g kg(-1) fresh weight), with approximately double the levels of current commercial cultivars. Temperature was shown to influence anthocyanin extraction, with 40 °C being the best extraction temperature using the accelerated solvent extraction (ASE) method. Hue angle and anthocyanin concentration showed a good correlation (r(2) = 0.69). CONCLUSION The new breeding line BL 2006-221 has the potential to be used in the development of phytochemically rich strawberry cultivars. Using hue angle as a screening tool for total anthocyanin concentration and extraction of anthocyanins from strawberries by ASE at 40 °C would support such cultivar development.

Potential Antioxidant, Antiinflammatory, and Proapoptotic Anticancer Activities of Kakadu Plum and Illawarra Plum Polyphenolic Fractions

Kakadu plum (Terminalia ferdinandiana Exell, Combretaceae) and Illawarra plum (Podocarpus elatus Endl., Podocarpaceae) extracts were fractionated, using a bioassay-guided approach and screened for antioxidant activity [oxygen radical absorbance capacity (ORAC) and cellular antioxidant activity (CAA) assays] and antiinflammatory activity (nitrite concentration and prostaglandin E2 release in lipopolysaccharide (LPS)-activated murine macrophages). Among 8 fractions obtained from KP and 5 fractions obtained from IP, fraction KPF5 from KP exhibited superior activity in all assays, with an ORAC value of 3,776 ± 603 μmol Trolox/g DW and a CAA value of 52.2 ± 8.6 μmol quercetin equivalents/g DW. In addition, KPF5 further demonstrated an upregulation of the Nrf2/Keap1 ratio in Hep G2 cells. KPF5 also inhibited the expression of COX-2 and iNOS in LPS-activated murine macrophages, potentially through the NF-κB, p44/42 mitogen activated protein kinase and Akt pathways. KPF5 also induced apoptosis and DNA damage in HT-29 cells, as determined by the cytokinesis block micronucleus cytome assay.

Molecular Size Fractions of Bay Leaf (Laurus nobilis) Exhibit Differentiated Regulation of Colorectal Cancer Cell Growth In Vitro

Numerous in vitro studies using solvent or aqueous extracts of raw dietary plant material have demonstrated modulation of colon cancer cell growth and apoptosis and effects on immune and nonimmune pathways of inflammation. We have developed a generic, 3-staged food-compatible process involving heating for conversion of dietary plants into food ingredients and report results on potential colon cancer-regulating properties of processed forms of Bay leaf (Laurus nobilis). In vitro studies demonstrated inhibition of cancer cell growth by processed Bay leaf products in HT-29, HCT-116, Caco-2, and SW-480 human cancer cell lines, which were accompanied by variable levels of elevated apoptosis. Bay leaf also exerted moderate inhibition of cycloxygenase 2 and 5 lipoxygenase enzymatic activity. In addition, these extracts significantly downregulated interferon-γ production in T helper Type 1-stimulated whole blood from healthy donors. Furthermore, size fractionation of the extracts revealed that antiproliferative and proapoptotic activities were associated with low mass (primarily polyphenolics and essential oils) and high mass (primarily proteins including polyphenol oxidase) chemical classes, respectively. Bay leaf exerted in vitro bioactivity that might be relevant to protecting against early events in sporadic colorectal cancer, with potential for further optimization of bioactivity by size-based fractionation.

Whey protein isolate improves vitamin B12 and folate status in elderly Australians with subclinical deficiency of vitamin B12

Scope: Whey protein isolate (WPI) contains vitamin B12 and folate. However, the efficacy of WPI as a bioavailable source of these vitamins in the elderly with low vitamin B12 was not previously tested. We investigated the effects of WPI supplementation on vitamin B12 and folate status in blood and measured changes in homocysteine (HCY), methylmalonic acid (MMA), and genome integrity biomarkers in elderly individuals with low vitamin B12 status. The effect of WPI was compared to soy protein isolate (SPI). Methods and results: In this randomized controlled cross‐over intervention trial, 56 subclinically vitamin B12‐deficient participants received 50 g WPI or 50 g SPI as a control for 8 wk followed by 16‐wk washout phase and then cross‐over to alternative supplement for next 8 wk. Consumption of WPI resulted in significant increase in serum active B12 (p < 0.0001) and serum folate (p = 0.0094). MMA, HCY, and nucleoplasmic bridges increased significantly after SPI intake but not after WPI (p = 0.052; p = 0.028; p = 0.0009, respectively). Conclusion: Results indicate that WPI consumption improves active B12 and folate status. Unlike SPI, WPI consumption may prevent increase in MMA, HCY, and genome instability in older Australians with low vitamin B12 status.

Olive Oil Adulteration with Hazelnut Oil and Analytical Approaches for Its Detection

Publisher Summary Adulteration of olive (Olea europaea) oil with vegetable, seed, or nut oils has become a serious problem for regulatory agencies, consumers, oil producers, and oil importers. Admixtures of olive oil with hazelnut (Corylus spp.) oil, in particular, represent one of the most recent challenges facing scientists and regulatory bodies. Although hazelnut oil is not associated with some of the health risks attributed to some of the other low-quality oils used to adulterate olive oil, the difference in economic value between the two oils causes an estimated loss of 4 million euros per year for countries in the European Union. In addition, the dietary intake of health-benefiting components found naturally in virgin olive oil (e.g. polyphenols, sterols, tocopherols) can be greatly reduced following consumption of oils adulterated with low-quality refined hazelnut oils. Detection of hazelnut oil in admixtures with olive oil has always been very difficult to confirm due to very similar chemical profiles exhibited by the two oils, especially in terms of triacylglycerols and fatty acids. Numerous chemical approaches have been proposed over the last 15 years that are able to detect various hazelnut oil/olive oil blends. Profitable olive oil adulteration by hazelnut oil, as with most other edible oils, can only be effected by one of three ways: virgin (also termed crude or pressed) hazelnut oil into virgin olive oil, refined hazelnut oil into virgin olive oil, and refined hazelnut oil into refined olive oil. This chapter presents an overview of the modern analytical approaches (proposed over the last two decades or so) and the current state of knowledge in each of the three adulteration scenarios.

Characterization of Date (Deglet Nour) Seed Free and Bound Polyphenols by High-Performance Liquid Chromatography-Mass Spectrometry

Date (Pheonix dactylifera L.) seeds are a valuable and abundant by-product with various potential food applications. Free polyphenols (FPPs) and bound polyphenols (BPPs) of date seeds from Deglet Nour variety grown in Australia were investigated using high-performance liquid chromatography-mass spectrometry. The FPP fraction contained the following main phenolic compounds per gram of date seed powder; procyanidin B1 (499.8 ± 7.8 μg), procyanidin B2 (288.6 ± 6.1 μg), catechin (167.6 ± 2.1 μg), epicatechin (39.44 ± 0.39 μg), and protocatechuic acid (1.77 ± 0.22 μg). Additionally, one of the 2 A-type dimers was confirmed as procyanidin A2 (24.05 ± 0.12 μg/g). A-type dimers have not been reported before in date seeds. The BPP fraction contained epicatechin (52.59 ± 0.76 μg/g) and procyanidin B2 (294.2 ± 3.7 μg/g), while several peaks exhibiting ESI- m/z of 153 indicated dihydroxybenzoic acid isomers including protocatechuic acid (2.138 ± 0.025 μg/g). These findings contributed to our knowledge of date seed phytochemicals and understanding of their contribution to the reported bioactivities.