Food for Thought Lecture Series
Adulteration of Table Olives
Olives (Olea europaea) are used for oil or served as table olives. Raw or fresh olives are naturally very bitter and in order to make them palatable, olives must be cured (e.g. by fermentation). Table olives are generally classified into 3 major groups according to the degree of ripeness prior to harvesting. Unripe-olives (green), semi-ripe olives (purple) and ripe-olives (black). Adulteration of table olives are common by artificial fermentation and adding colour compounds completely foreign to the natural pigment of olives. For example, artificial ripening type is a way to turn green olives to black olives without fermentation. Olives are picked green, then injected with compressed air. The air oxidises the skin and flesh of the fruit, turning it black in an artificial process that mimics natural ripening. Ferrous gluconate or lactate are two colour agents that are added to complete the process.
Once olives are fully oxidized or "blackened", they are brined and acid corrected ready for the market. Green olives treated with copper sulphate to brighten their colour. Overexposure to copper sulphate, normally used in pesticide products, can cause nausea, vomiting and abdominal pain. It can be lethal in some cases. Misleading consumers by using altered words such as acidifier instead of artificial colour or additives can cause consumption of hazardous materials by consumers. A red colour that artificially converts green olives to red olives can cause thyroid disorders. Governments must improve food regulations, especially on imported foods such as olive and olive oil to prevent fraudulent practice. Additionally, awareness of public through media and educational institutes will help consumer to better understand what they get from their foods. Are they eating real ripe-black olives or oxidized/blackened olives with dye?
The presentation will be in English only with a bilingual Q & A.
Farah Hosseinian, Associate Professor, Food Science and Nutrition, Carleton University
My research program focuses on the investigation of novel bioactives/biomolecules compounds from agri-food by-products/waste (e.g. flaxseed and soybean meal, legumes hull, berries pulp and skin) with potential of antioxidant, anti-inflammatory and prebiotic/probiotic activity. These biomolecules can be used in food, feed and pharmaceutical applications. Our focus is mainly on phenolics and dietary fibre (e.g. mucilage, okara, and inulin). Since dietary fibre and phenolics are conjugated in plants, we call them glyco-phenolics. Basically, we believe dietary fibre are carrier of phenolics. We use fermentation models, particularly “kefir model” to investigate if glyco-phenolics can enhance solubility of key minerals (Ca, P, Mg) as biomarkers of bioactive dietary fibre in addition to antioxidant activity from the conjugated phenolics. Furthermore, we use solvent-free environmentally friendly extraction methods including supercritical-CO2 and microwave assisted technology to extract these biomolecules. Working on agri-food waste in combination with solvent-free extraction techniques, will help agricultural and environmental sustainability. I teach adulteration of foods (e.g. chocolate or olives/olive oil). For example, adulteration of olive oil with canola oil using specific techniques is discussed in order to distinguish between the above oils. Also I teach how green olives can convert to black olives artificially. The variety of tests are discussed to distinguish the two olives. I am founder of Jerusalem Artichoke Association of Canada (JAAC) looking at JA as future clean sugar in our diet.Back to top