Chakra Wijesundera

DHA-Containing Oilseed: A Timely Solution for the Sustainability Issues Surrounding Fish Oil Sources of the Health-Benefitting Long-Chain Omega-3 Oils

Benefits of long-chain (≥C20) omega-3 oils (LC omega-3 oils) for reduction of the risk of a range of disorders are well documented. The benefits result from eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA); optimal intake levels of these bioactive fatty acids for maintenance of normal health and prevention of diseases have been developed and adopted by national and international health agencies and science bodies. These developments have led to increased consumer demand for LC omega-3 oils and, coupled with increasing global population, will impact on future sustainable supply of fish. Seafood supply from aquaculture has risen over the past decades and it relies on harvest of wild catch fisheries also for its fish oil needs. Alternate sources of LC omega-3 oils are being pursued, including genetically modified soybean rich in shorter-chain stearidonic acid (SDA, 18:4ω3). However, neither oils from traditional oilseeds such as linseed, nor the SDA soybean oil have shown efficient conversion to DHA. A recent breakthrough has seen the demonstration of a land plant-based oil enriched in DHA, and with omega-6 PUFA levels close to that occurring in marine sources of EPA and DHA. We review alternative sources of DHA supply with emphasis on the need for land plant oils containing EPA and DHA.

Application of zNose™ for the analysis of selected grape aroma compounds

A novel and portable gas chromatograph (GC, zNosetrade mark) has been evaluated for the measurement in grape berries of selected six-carbon compounds; namely, hexanal, cis-2-hexen-1-ol, cis-3-hexen-1-ol and trans-2-hexenal. The zNosetrade mark is a handheld GC which uses purge and trap for concentration, and has a surface acoustic wave (SAW) sensor as a detector. Operation of the zNosetrade mark using direct aspiration of the sample failed to detect the compounds at the reported odour threshold values. Pre-concentration by Tenax((R)) trapping and solid-phase microextraction (SPME) were investigated to improve the zNosetrade mark sensitivity. Use of a Tenax((R)) pre-trap with the zNosetrade mark allowed detection of the compounds at concentration levels in the order of their threshold values. Excessive bleed from the SPME fibre prevented the use of SPME with zNosetrade mark.

Stabilization of Fish Oil‐in‐Water Emulsions with Oleosin Extracted from Canola Meal

International dietary guidelines advocate replacement of saturated and trans fat in food with unsaturated oils. Also, there is growing interest in incorporating highly unsaturated omega-3 oils in to food products due to beneficial health effects. A major obstacle to incorporating highly unsaturated oils in to food products is the extreme susceptibility to oxidative deterioration. Oil bodies were prepared from tuna oil, oleosin, and phospholipid mimicking natural oil bodies within oilseed. Oleosin was extracted from canola (Brassica napus) meal by solubilization in aqueous sodium hydroxide (pH 12) and subsequent precipitation at its isoelectric point of pH 6.5. The tuna oil artificial oil bodies (AOBs) readily dispersed in water to produce oil-in-water (o/w) emulsions, which did not coalesce on storage and were amenable to pasteurization using standard conditions. Accelerated oxidation studies showed that these AOB emulsions were substantially more resistant to lipid oxidation than o/w emulsions prepared from tuna oil using Tween40, sodium caseinate, and commercial canola protein isolate, respectively. There is potential to use commercial canola meal, which is cheap and abundant, as a natural source of oleosin for the preparation of physically and oxidatively stable food emulsions containing highly unsaturated oils.

Rapid isolation of omega-3 long-chain polyunsaturated fatty acids using monolithic high performance liquid chromatography columns.

Eicosapentaenoic and docosahexaenoic acids are important bio-active fatty acids in fish oils. Monolithic HPLC columns both in the polymeric cation exchange (silver-ion) and RP formats were compared with corresponding packed columns for the isolation of these acids from tuna oil ethyl esters. Monolithic columns in both formats enabled rapid (typically 5-10 min) separations compared with packed columns (30 min). Polymeric monolithic silver-ion disc column rapidly furnished mixtures of eicosapentaenoic and docosahexaenoic esters (90% purity) within 5-10 min, but was unable to resolve individual esters. A preparative version of the same column (80 mL bed volume) enabled isolation (>88% purity) of 100 mg quantities of eicosapentaenoic and docosahexaenoic esters from esterified tuna oil within 6 min. Baseline separation of eicosapentaenoic and docosahexaenoic esters was achieved on all RP columns. The results show that there is potential to use polymeric monolithic cation exchange columns for scaled-up preparation of eicosapentaenoic and docosahexaenoic ester concentrates from fish oils.

Effect of docosahexaenoic acid and furan fatty acids on cytokinesis block micronucleus cytome assay biomarkers in astrocytoma cell lines under conditions of oxidative stress.

Fatty acids from fish such as docosahexaenoic acid (DHA) are associated with improved brain function, whereas furan fatty acids (FFAs) also found in fish oil at low levels (1%) are thought to have antioxidant properties. Understanding their effects in astrocytes is important as these cells are responsible for maintaining healthy neurons via lipid homeostasis and distribution within the brain, and their decline with aging is a possible cause of dementia. We investigated the cytotoxic and genotoxic effects of DHA and FFA using the cytokinesis‐block micronucleus cytome assay in in vitro cultures of U87MG (APOE ɛ3/ɛ3) and U118MG (APOE ɛ2/ɛ4) astrocytoma cell lines with and without a hydrogen peroxide (H2O2, 100 µM) challenge. U118MG was found to be more sensitive to the cytostatic, cytotoxic (i.e., apoptosis), and DNA damaging effects [micronuclei (MNi), nucleoplasmic bridges (NPBs), and nuclear buds (NBUDs)] of H2O2 (P < 0.01 and P < 0.001) when compared with U87MG. DHA at 100 µg/mL significantly affected cytostasis (P < 0.05) and increased DNA damage in the form of NPBs and MNi (P < 0.05) in both cell lines, whereas it decreased necrosis (P = 0.0251) in U87MG. Significant DHA–H2O2 interactions were observed for decreased necrosis (P = 0.0033) and DNA damage biomarkers (P < 0.0001) in the U87MG cell line and increased cytostasis (P < 0.0001) in the U118MG cell line. The effects of FFA also varied between the cell lines, with significant effects observed in decreased cytostasis (P = 0.0022) in the U87MG cell line, whereas increasing cytostasis (P = 0.0144) in the U118MG cell line. Overall, FFA exerted minimal effects on DNA damage biomarkers. Environ. Mol. Mutagen. 55:573–590, 2014.

Trans Fats Replacement Solutions in Australia and New Zealand

Publisher Summary With increasing evidence to support that Trans Fatty Acids (TFAs) pose a higher risk of Coronary Heart Disease (CHD) compared to Saturated Fatty Acids (SFA), nutritional bodies continue to advocate reductions in TFA intake. Several countries have introduced legislation aimed at reducing dietary intake of TFAs. Denmark and several other European countries placed limits on the TFA content in foods that can be sold to consumers, while several other countries, including Canada and the United States, required that the TFA content is displayed on the product label if it exceeds a specified amount per serving. More recently, Singapore also has introduced TFA labeling regulations, while China is in the process of introducing legislation that makes it mandatory to declare TFAs on the nutrition label if partially hydrogenated fats have been used in product manufacture. Since the introduction of food labeling regulations, there have been marked declines in the TFA content in the food supplies of both Canada and the United States, and these reductions have been achieved without causing a significant increase in saturated fats. Australia and New Zealand are yet to introduce any compositional regulatory measures in relation to TFA in the food supply. Instead, the authorities have adopted a position of encouraging the food industry to voluntarily implement strategies to reduce the TFA content in the foods they manufacture. This chapter reviews various surveys conducted from 1970 onward on the TFA content of foods in Australia and New Zealand and discusses the measures adopted by regulatory authorities and industry to achieve a reduction in TFA intake by Australians and New Zealanders.