Dr. Yvonne Yuan, Associate Professor – Ryerson University

Yvonne Yuan (PhD) is an associate professor in the School of Nutrition, Ryerson University where her teaching and research are focused on food chemistry related to functional foods and chronic disease risk factors and health. Her research program is focused on the antioxidant and biological activities of plant foods, specifically edible marine macroalgae (seaweeds) from Western and Atlantic Canada. She recently co-edited a book entitled “Recent Advances in Micro- and Macroalgal Processing: Food and Health Perspectives”.

Yvonne is a past chair of the Nutrition Interest Division for the CIFST and has served on the Board of Directors since 2019.

PRESENTATION:

Edible red seaweeds as functional foods and sources of nutraceuticals.

Seaweeds are the quintessential functional food and source of nutraceuticals, playing an important role in the diets of coastal peoples across the globe, attributable to the macro- and micronutrient contents, flavor and texture enhancing properties of the various marine macroalgae. These seaweeds include many species from the Rhodophyta such as “Nori” or “Kim/Gim” in Japan and Korea, “Dulse/Dillisk” in Ireland, Canada or U.S.A., or “Irish Moss” in the Caribbean. Medicinal or functional food properties of edible seaweed were used in the treatment or prevention of chronic disease risks such as breast cancer, as far back as approx. 1534 B.C. in the Egyptian ‘Ebers Papyrus’. Ethnobotanical studies indicate that indigenous peoples of the Pacific coast of Canada (British Columbia) and the U.S.A (Alaska) have a long history of macroalgae usage, particularly, Porphyra abbottiae (also known as Pyropia abbottiae) for nutrition, medicinal and trade practices. Rhodophyta (red seaweeds) are notable for containing UV-absorbing mycosporine-like amino acids (MAAs) with sunscreen and antioxidant activities. In this work, the MAA profiles, reducing activities, oxygen radical absorbance capacities (ORAC) and antiproliferative activities of methanol extracts of wild-harvested (Chondrus crispus, Mastocarpus stellatus, Palmaria palmata) and cultivated edible red seaweeds (Chondracanthus chamissoi, Fredericqia deveauniensis, Sarcodiotheca gaudichaudii) were determined. MAAs confirmed by LC/MS/MS in extracts were palythine, asterina-330, shinorine, palythinol, porphyra-334 and usujirene. Extract reducing activities in descending order were: P. palmata > F. deveauniensis ≥ S. gaudichaudii Parent = M. stellatus = S. gaudichaudii Variant = C. chamissoi > C. crispus; and ORAC values were: M. stellatus > P. palmata > F. deveauniensis > C. crispus > S. gaudichaudii Variant = S. gaudichaudii Parent = C. chamissoi. HeLa and Caco-2 cell proliferation were inhibited (p < 0.001) in a dose- and species-dependent manner by extracts from 0.125-4 mg/mL, after 72 hrs incubation. Extracts containing low-polarity usujirene and polar shinorine (P. palmata, M. stellatus) were particularly antiproliferative. Others rich in polar palythine and asterina-330 (C. crispus) also exhibited strong antiproliferation. Antiproliferative activities were associated with executioner caspase-3/7 induction and apoptosis. This work can help to further the development of Canadian mariculture producers and processors of edible marine red seaweeds in the processed and functional food and nutraceutical industries.

Folake Oyewole, Ph.D. Candidate – University of Toronto

Folake is a 5th year Ph. D. candidate in the Department of Chemical Engineering and Applied Chemistry, University of Toronto. She is a member of the Food Engineering Research Group and is supervised by Professor Levente Diosady. Her thesis is focussed on developing a functional beverage from a sub-Saharan African indigenous herb: Hibiscus sabdariffa, to address the prevalence of iron deficiency within the region and other tropical regions where the beverage is commonly consumed.

Folake has over 10 years of research experience in natural product development and value added processing. She is on study leave from her role as a research scientist at the foremost industrial research institute in Nigeria, the Federal Institute of Industrial Research, Oshodi, Lagos, Nigeria. 

PRESENTATION:

A Study to Improve the Bioaccessibility of Native Iron and Added Iron in Hibiscus Sabdariffa Beverage, a Potential Iron Delivery Vehicle

Herbal plants rich in minerals, vitamins and bioactive compounds are of growing interest to researchers and consumers because of their perceived nutritional and therapeutic benefits. There has been a recent focus on the Hibiscus sabdariffa plant because all its parts are believed to be useful. H. sabdariffa belongs to the Malvaceae family and its common names include hibiscus and roselle. It is ubiquitous in the tropics, including many countries in sub-Saharan Africa. Reportedly, the plant’s calyces, its most useful part, is a good source of nutrients and phytochemicals also, which impart therapeutic properties. The vibrantly red aqueous extract of the calyces of the plant is commonly consumed as a hot or cold beverage. A few studies have suggested that since the hibiscus beverage has a relatively high iron content, it may be a viable option as an iron source in regions like sub-Saharan Africa.

Sub-Saharan Africa has an alarming prevalence of iron deficiency. Iron deficiency is a public health challenge of significance that has persisted in the region for decades. It is a leading cause of anemia, contributing to about 50% of the global anemia burden. The consequences of iron deficiency could be quite devastating, resulting in increased rates of maternal and infant mortality, motor and cognitive developmental impairments and unwanted pregnancy outcomes. A Micronutrient Forum Report in 2017, estimated that iron deficiency contributes to 600,000 stillbirths and over 100,000 maternal deaths annually.

Indeed, the import of iron deficiency cannot be overstated, especially as it invariably affects the productivity of the affected populations, leading to a vicious cycle of ill health, poverty, and even more iron deficiency.

In response, the present study investigated H. sabdariffa beverage’s potential as an iron source as well as a fortification vehicle, to cover gaps in current interventions addressing the prevalence of iron deficiency in sub-Saharan Africa. Specifically, because the beverage has a generous quantity of polyphenols, a known iron absorption inhibitor, the focus was on the quantitation and prevention of the chelation complex formed between iron and polyphenols.

First, the hibiscus beverage was characterized to determine how much iron was transferred into it, from the raw calyces during the extraction process. An inductively coupled plasma -atomic emission spectrophotometer (ICP-AES) was used to quantify iron in all samples. The target was to have 6 mg of iron in 250 mL (assumed to be the daily consumption volume per person) of the beverage, providing 30% of the recommended dietary allowance of iron for a premenopausal woman: 18 mg/ day. The extractability expressed as a percentage was determined to be 31.8 ± 6.7%, suggesting that most of the iron stayed bound to the residual solid after extraction.

Next, a 2 3 factorial experiment was carried out to determine the extraction conditions that would result in the highest iron yield while aiming to keep the polyphenolic content close to those of commercially sold hibiscus beverages. The polyphenolic content was determined using the Folin Ciocalteu method. Polyphenols are also known to impart organoleptic properties, so it was important to keep the polyphenolic content in a range already acceptable to consumers. It was determined that 12.5% w/v of the dry calyces in reverse osmosis water, heated to a temperature of 90°C for 30 minutes and with 30 minutes steeping time gave the best iron yield of 0.93±0.19 mg/250 mL. The molar ratio of the iron to polyphenol in this selected “working beverage sample” was determined to be ~1:25, demonstrating an overage of polyphenols. This suggest that possibly, the polyphenols would also interact with any added iron. Ferrous sulphate heptahydrate (FeSO4.7H2O) salt was added as an iron fortificant to meet the targeted iron concentration in the beverage.

Then, using a Tecan infinite 200 pro microplate reader, a spectrophotometric method was adapted to evaluate the ironpolyphenol chelation complexes formed between polyphenols and the native and added iron (fortificant), separately. The reaction between gallic acid and ferrous sulphate served as the model reaction. All samples were pH adjusted to 6.5 to mimic conditions at the site of iron absorption in the gastrointestinal (GI) tract, the small intestine. The absorbance scans of both sets of samples, the unfortified and fortified beverages, showed clear peaks at the expected wavelength for the ironpolyphenol complex. From the results. It could therefore be inferred that most of the iron was not available to be absorbed during digestion.

Finally, a competing chelating agent, disodium EDTA (Na2EDTA), was introduced into both the unfortified and fortified hibiscus beverages and this resulted in peak drops. Indicating that introducing the competing chelation made the iron more bioaccsessible. The ratio of Fe to Na2EDTA was varied for both set of hibiscus samples at ratios 1:0; 1:1; 1:2; 1:3 and 1:4 (Fe: Na2EDTA). Ratio 1:2, which had been suggested in a similar study as the optimum ratio, released 20% and 80% of the native iron and added iron respectively. Suggesting that the bioaccessibility of the added iron significantly improved when the competing chelating agent was introduced into the beverage. However, the same degree of increased bioaccessibility wasn’t seen with the native iron.

Ultimately, the results suggest that with the addition of the competing chelating agent: disodium EDTA, the iron in the fortified and unfortified H. sabdariffa beverages became more bioaccessible. However, on its own, the unfortified hibiscus beverage is not able to significantly improve the iron status of consumers of the beverage.

Dr. Olayinka Oluwagunwa, Postdoctoral Research Fellow – University of Manitoba

PRESENTATION:

Telfairia occidentalis

Telfairia occidentalis, commonly known as fluted pumpkin is a plant that is native to Nigeria and other parts of West Africa. It is locally referred to as ugu and planted basically for its edible leaves and seeds. It belongs to the Cucurbitaceae family, and the leaves are popular ingredients in soup preparations. Chlorophyll is the green pigment present in plants for photosynthesis process but also has a good antioxidant property that could quench the effect of free radicals and function therapeutically to remove toxins from the blood, as well as prevent cancer and other types of diseases. Chlorophylls can contribute to the antioxidant properties of plant extracts, but excessive levels could also become prooxidant with damaging effects to health. Therefore, this work aims to determine the effect of chlorophyll reduction on the antioxidant, antihypertensive and enzyme inhibition properties of Telfairia occidentalis polyphenolic fractions. Telfairia occidentalis leaf aqueous extract (TO) was fractionated into chlorophyll-enriched (CH-E) and chlorophyll-reduced (CH-R) fractions followed by comparative evaluation of their antioxidant and enzyme inhibition properties. Total chlorophyll content of CH-E was 46.22 ± 0.16 mg/g when compared to 25.29 ± 0.21 and 37.84 ± 0.21 mg/g for CH-R and TO, respectively. The CH-E and TO had significantly (p < 0.05) higher ferric reducing antioxidant power and total antioxidant capacity than the CH-R fraction. In contrast, the CH-E and CH-R had significantly (p < 0.05) higher superoxide radical scavenging activity than the TO. The CH-R also had significantly (p < 0.05) higher α-amylase, pancreatic lipase, acetylcholinesterase, and DPP-IV inhibitory activities of CH-R. However, the CH-E had significantly (p < 0.05) stronger inhibitions of α-glucosidase, and renin than the CH-R while TO inhibited ACE more than the fractions. Keywords: Polyphenols, chlorophyll, Telfairia occidentalis, antioxidant, enzyme inhibition, circular dichroism, intrinsic fluorescence.

Prabhjot Kaur – University of Guelph

PRESENTATION:

Potential of sour-cherry cultivars (Ontario) as an emerging functional food

Sour cherries have been considered an excellent source of bioactive components such as phenolic compounds, antioxidants, and several nutrients and are considered as “Super-foods” due to numerous health benefits. The production and consumption of these fruits are being revived due to their high-value potential. This study aimed to characterize the different physicochemical properties of sour cherry cultivars grown in Ontario, Canada and identify the most promising cultivar(s) providing maximum health-promoting components. In this study, the bioactive components such as total phenolic content, total and monomeric anthocyanin content, total flavonoids, and antioxidant activity of 10 sour cherry cultivars were investigated. Chemo-metric and metabolomics analysis of the sour cherry cultivars was done by HPLC and UPLC-MS to study the metabolites and bioactive component profile. Antimicrobial activity of these cultivars was checked for plant pathogenic organisms. Further, the anti-diabetic activity of the sour cherry was assessed with the in-vitro inhibition of α-glucosidase and dipeptidyl peptidase-4 enzymes. Physicochemical analysis of 10 sour-cherry cultivars revealed that dark-colored varieties contained higher phenolic content (1.9-2.162mg GAE/g FW), total anthocyanin (3.6-4.1 mg Cyanidin-3-O-glucoside eq. /g FW), total flavonoids (0.0068-0.0079 mg Rutin eq./ g FW), and antioxidant potential by FRAP (24.7-27.58 mM Trolox/g FW), ABTS, and DPPH (11-12.5 mM Trolox/g FW). UPLC-MS analysis identified 40 functional components at significant levels comprising major phenolic compounds (anthocyanin, flavonoids, hydroxycinnamic derivatives, rutin, gallic acid, etc.), antioxidants, and melatonin. The dark colored cultivars provided significant antimicrobial activity against plant pathogens. The two cultivars (Heimann R and Gorsemska) exhibited significant antidiabetic activity by in-vitro inhibition of glucosidase and peptidase enzymes due to its high polyphenolic content. The comprehensive evaluation of bioactive components and metabolites suggested that the dark-colored sour cherry cultivars are a better source of nutraceutical components and dietary supplements.