The quality indices and chemical composition of ten common olive cultivars grown in different regions of Australia were evaluated to determine the diversity of olive oils produced in Australia. Olives from trees from different environments including warmer climates in the north to colder climates in the south were sampled at two different stages of maturity over 2 years. The oil was extracted and standard methods were used to analyse the oil. Oleic acid content ranged from 83.4% in the Picual cultivar grown in Tasmania to 54.5% in Arbequina grown in northern New South Wales/southern Queensland. The Barnea cultivar, which is very commonly grown in Australia, was above 4% for campesterol content, regardless of the region in which it was grown. Parameters, such as palmitic acid, oleic acid, linoleic acid and wax content were found to be significantly affected by growing region for some cultivars. This study shows the growing conditions for olive in Australia gives rise to a diverse range of olive oils.

Canola meal is highly regarded as a component of animal feed with a high protein content and a desirable amino acid profile. The presence of some components, in particular glucosinolates, sinapine and fibre, affects the value of the meal and reduces the amount that can be used in animal feed formulations. Glucosinolates in traditional cultivars (rapeseed) had very high amounts and this severely limited the usefulness of the meal. Canola breeding programs have successfully reduced glucosinolate content to trace amounts. However sinapine remains at levels sufficiently high to cause problems, particularly in poultry feed. The relatively high fibre level in canola also reduces the value of the product for animal feed. This study has determined the level of sinapine, glucosinolates and fibre in current cultivars of canola in Australia to illustrate advances made by breeding programs and limitations which still remain to raise the usefulness of a potentially valuable feedstock. Although glucosinolate levels in meal were shown to have been reduced to 11 lmol/g in some cases, sinapine remained at traditional levels of about 12-15 g/kg and neutral detergent fibre levels were about 30-40%. These issues are important priorities for canola breeders.

For compound 14, the 13 C NMR δ value of 22.0 (t) should be replaced by 39.3 (t).

BackgroundDeep frying in oil is a popular cooking method around the world. However, the safety of deep-fried edible oil, which is ingested with fried food, is a concern, because the oil is exposed continuously to be re-used at a high temperature, leading to a number of well-known chemical reactions. Thus, this study investigates the changes in energy metabolism, colon histology and gut microbiota in rats following deep-fried oil consumption and explores the mechanisms involved in above alterations.MethodsDeep-fried oil was prepared following a published method. Adult male Wistar rats were randomly divided into three groups (n = 8/group). Group 1: basal diet without extra oil consumption (control group); Group 2: basal diet supplemented with non-heated canola oil (NEO group); Group 3: basal diet supplemented with deep-fried canola oil (DFEO group). One point five milliliters (1.5 mL) of non-heated or heated oil were fed by oral gavage using a feeding needle once daily for 6 consecutive weeks. Effect of DFEO on rats body weight, KEGG pathway regarding lipids metabolism, gut histology and gut microbiota were analyzed using techniques of RNA sequencing, HiSeq Illumina sequencing platform, etc.ResultsAmong the three groups, DFEO diet resulted in a lowest rat body weight. Metabolic pathway analysis showed 13 significantly enriched KEGG pathways in Control versus NEO group, and the majority of these were linked to carbohydrate, lipid and amino acid metabolisms. Comparison of NEO group versus DFEO group, highlighted significantly enriched functional pathways were mainly associated with chronic diseases. Among them, only one metabolism pathway (i.e. glycerolipid metabolism pathway) was found to be significantly enriched, indicating that inhibition of this metabolism pathway (glycerolipid metabolism) may be a response to the reduction in energy metabolism in the rats of DFEO group. Related gene analysis indicated that the down-regulation of Lpin1 seems to be highly associated with the inhibition of glycerolipid metabolism pathway. Histological analysis of gastrointestinal tract demonstrated several changes induced by DFEO on intestinal mucosa with associated destruction of endocrine tissue and the evidence of inflammation. Microbiota data showed that rats in DFEO group had the lowest proportion of Prevotella and the highest proportion of Bacteroides among the three groups. In particular, rats in DFEO group were characterized with higher presence of Allobaculum (Firmicutes), but not in control and NEO groups.ConclusionThis study investigated the negative effect of DFEO on health, in which DFEO could impair glycerolipid metabolism, destroy gut histological structure and unbalance microbiota profile. More importantly, this is the first attempt to reveal the mechanism involved in these changes, which may provide the guideline for designing health diet.Electronic supplementary materialThe online version of this article (doi:10.1186/s12944-016-0252-1) contains supplementary material, which is available to authorized users.

Harvest time plays a key role in the quality and oxidative stability of olive oil. Olive producers can control oil quality by using appropriate harvest times. Fruits from three olive cultivars, Corregiolla, Mission and Paragon growing in the southwestern region of New South Wales, Australia, were harvested at six different times during the season, over 3 years and immediately processed in a laboratory scale mill. The oils were then analyzed for total polyphenol content, induction time, chlorophyll content and fatty acid profile. The maturity index of the fruit was also determined. Most parameters measured, including polyphenols, induction time and fatty acids, showed a significant year effect. Cultivar effects were also apparent with total polyphenols content in cv. Mission being consistently higher than in the other cultivars studied. There was a strong interaction between the parameters studied, particularly between total polyphenol content and induction time, with high polyphenol content increasing oil oxidative stability. The fatty acid profiles of the oils were found to be strongly influenced by the growing season. Generally, as the fruit matured, the oil became less stable due to decreasing total polyphenol content, increasing polyunsaturates (mainly linoleic acid), and decreasing chlorophyll content.