Quality Assessment of Burdekin Plum (Pleiogynium timoriense) during Ambient Storage.

Pleiogynium timoriense, commonly known as Burdekin plum (BP), is among many Australian native plants traditionally used by Indigenous people. However, only limited information is available on the nutritional and sensory quality of BP grown in Australia as well as its changes during storage. Therefore, this study evaluated the quality of BP during one week of ambient storage (temperature 21 °C, humidity 69%). Proximate analysis revealed a relatively high dietary fiber content in BP (7-10 g/100 g FW). A significant reduction in fruit weight and firmness (15-30% and 60-90%, respectively) with distinguishable changes in flesh color (ΔE > 3) and an increase in total soluble solids (from 11 to 21 °Brix) could be observed during storage. The vitamin C and folate contents in BP ranged from 29 to 59 mg/100g FW and 0.3 to 5.9 µg/100g FW, respectively, after harvesting. A total phenolic content of up to 20 mg GAE/g FW and ferric reducing antioxidant power of up to 400 µmol Fe2+/g FW in BP indicate a strong antioxidant capacity. In total, 34 individual phenolic compounds were tentatively identified in BP including cyanidin 3-galactoside, ellagic acid and gallotannins as the main phenolics. Principle component analysis (PCA) of the quantified phenolics indicated that tree to tree variation had a bigger impact on the phenolic composition of BP than ambient storage. Sensory evaluation also revealed the diversity in aroma, appearance, texture, flavor and aftertaste of BP. The results of this study provide crucial information for consumers, growers and food processors.

Chemical composition of bunya nuts (Araucaria bidwillii) compared to Araucaria angustifolia and Araucaria araucana species.

Three of nineteen Araucaria tree species from around the world produce large edible seeds. While composition is established for edible pinhão and piñones nuts from Brazil and Chile, respectively, the first detailed characterisation for the composition of edible Araucaria bidwillii (bunya nut) from Australia is provided. Almost half of the kernel weight is moisture and the main component in the dried kernel is starch. Whilst low in protein and fat, it contains all essential amino acids and half the fatty acids are polyunsaturated (Omega-3 and 6). Bunya nuts are a source of dietary fibre, folate and minerals (Cu, Mn, Fe, Mg), while the nut husks and inner coating are high in phenolics, mainly catechin. The composition supports the Traditional Knowledge of Aboriginal Australians that the bunya nut is an energy dense and nutrient rich food. Similarities in the composition among the three different edible varieties were found, which should assist in developing sustainable value chain propositions via shared knowledge on processing and utilisation.

Degradation of the Indospicine Toxin from Indigofera spicata by a Mixed Population of Rumen Bacteria.

The leguminous plant species, Indigofera linnaei and Indigofera spicata are distributed throughout the rangeland regions of Australia and the compound indospicine (L-2-amino-6-amidinohexanoic acid) found in these palatable forage plants acts as a hepatotoxin and can accumulate in the meat of ruminant livestock and wild camels. In this study, bovine rumen fluid was cultivated in an in vitro fermentation system provided with Indigofera spicata plant material and the ability of the resulting mixed microbial populations to degrade indospicine was determined using UPLC-MS/MS over a 14 day time period. The microbial populations of the fermentation system were determined using 16S rRNA gene amplicon sequencing and showed distinct, time-related changes occurring as the rumen-derived microbes adapted to the fermentation conditions and the nutritional substrates provided by the Indigofera plant material. Within eight days of commencement, indospicine was completely degraded by the microbes cultivated within the fermenter, forming the degradation products 2-aminopimelamic acid and 2-aminopimelic acid within a 24 h time period. The in vitro fermentation approach enabled the development of a specifically adapted, mixed microbial population which has the potential to be used as a rumen drench for reducing the toxic side-effects and toxin accumulation associated with ingestion of Indigofera plant material by grazing ruminant livestock.

Metabolism of Black Carrot Polyphenols during In Vitro Fermentation is Not Affected by Cellulose or Cell Wall Association.

Fruit and vegetable polyphenols are associated with health benefits, and those not absorbed could be fermented by the gastro-intestinal tract microbiota. Many fermentation studies focus on "pure" polyphenols, rather than those associated with plant cell walls (PCW). Black carrots (BlkC), are an ideal model plant food as their polyphenols bind to PCW with minimal release after gastro-intestinal digestion. BlkC were fractionated into three components-supernatant, pellet after centrifugation, and whole puree. Bacterial cellulose (BCell) was soaked in supernatant (BCell&S) as a model substrate. All substrates were fermented in vitro with a pig faecal inoculum. Gas kinetics, short chain fatty acids, and ammonium production, and changes in anthocyanins and phenolic acids were compared. This study showed that metabolism of BlkC polyphenols during in vitro fermentation was not affected by cellulose/cell wall association. In addition, BCell&S is an appropriate model to represent BlkC fermentation, suggesting the potential to examine fermentability of PCW-associated polyphenols in other fruits/vegetables.

Low anthocyanin plum nectar does not impact cognition, blood pressure and gut microbiota in healthy older adults: A randomized crossover trial.

Queen Garnet plum (QGP), known for its high levels of anthocyanins, is a hybrid of the Japanese plum developed in Queensland, Australia. Anthocyanins provide the red, blue, and purple pigments in plants with demonstrated beneficial health effects. This study hypothesized that low-dose anthocyanin QGP intake will have a significant positive effect on cognition, blood pressure, and gut microbiota in healthy older adults. A randomized crossover trial was conducted to determine the effect and within subject variance on cognition and 24 hr. ambulatory blood pressure in older adults without cognitive impairment following daily consumption of 200 mL low-dose anthocyanin (5 mg/100 g) QGP nectar (intervention) or raspberry cordial (control). Secondary outcomes included inflammatory markers (C-reactive protein), nerve growth factor (BDNF), and gut microbiota (16S rRNA gene sequencing). Twenty-eight participants (55+ years) were recruited. Each randomized treatment arm lasted for 8 weeks with a 4-week washout period. Cognition, blood pressure, and urine samples were measured at each visit (5 total) while blood and fecal samples were collected at baseline, 8 weeks, and 20 weeks. Repeated-measures ANOVA was used to analyze the data. Across the treatments, no significant difference was observed for the different domains of cognition, blood pressure, or anti-inflammatory biomarkers. No intervention effect was found for genera or class of gut microbes. Low anthocyanin nectar derived from the QGP did not have any significant effects on cognition, blood pressure, or gut microbiota in healthy older adults.

Food Safety and Natural Toxins.

Natural toxins are poisonous secondary metabolites produced by living organisms, which are typically not harmful to the organisms themselves but can impact on human or animal health when consumed [...].

Phytochemical Characteristics and Antimicrobial Activity of Australian Grown Garlic (Allium Sativum L.) Cultivars.

This study systematically evaluated the main bioactive compounds and associated biological properties of two Australian grown garlic cultivars and commercial non-Australian grown garlic (for comparison purposes only). Additionally, the distribution of bioactive compounds in garlic skin and clove samples was determined to obtain a better understanding of the potential biological functionality of the different garlic parts. The identification and quantification of bioactive compounds was performed by ultra-high performance liquid chromatography with mass spectrometry and photodiode array detection (UHPLC-PDA-MS). A principal component analysis was applied to assess the correlation between the determined bioactive compounds and antioxidant capacity as well as antimicrobial activity. The content of phenolic compounds (free and bound forms) in the garlic skin samples was significantly (p < 0.05) higher than that of the garlic cloves, and was also higher (p < 0.05) in the Australian grown cultivars compared to the commercial non-Australian grown garlic. Anthocyanins were found in the skin samples of the Australian grown garlic cultivars. The organosulfur compounds were higher (p < 0.05) in the cloves compared to the skin samples and higher (p < 0.05) in the Australian grown cultivars compared to the studied commercial sample. As the richer source of bioactive compounds, the Australian grown garlic cultivars exhibited a significantly (p < 0.05) higher antioxidant capacity and stronger (p < 0.05) antimicrobial activity than the commercial non-Australian grown garlic. The potential of garlic cultivars rich in bioactive compounds for domestic and industrial applications, e.g., condiment and natural food preservative, should be explored further.

Bioaccumulation and Distribution of Indospicine and Its Foregut Metabolites in Camels Fed Indigofera spicata.

In vitro experiments have demonstrated that camel foregut-fluid has the capacity to metabolize indospicine, a natural toxin which causes hepatotoxicosis, but such metabolism is in competition with absorption and outflow of indospicine from the different segments of the digestive system. Six young camels were fed Indigofera spicata (337 µg indospicine/kg BW/day) for 32 days, at which time three camels were euthanized. The remaining camels were monitored for a further 100 days after cessation of this indospicine diet. In a retrospective investigation, relative levels of indospicine foregut-metabolism products were examined by UHPLC-MS/MS in plasma, collected during both accumulation and depletion stages of this experiment. The metabolite 2-aminopimelamic acid could be detected at low levels in almost all plasma samples, whereas 2-aminopimelic acid could not be detected. In the euthanized camels, 2-aminopimelamic acid could be found in all tissues except muscle, whereas 2-aminopimelic acid was only found in the kidney, pancreas, and liver tissues. The clearance rate for these metabolites was considerably greater than for indospicine, which was still present in plasma of the remaining camels 100 days after cessation of Indigofera consumption.

Assessing the risk of residues of the toxin indospicine in bovine muscle and liver from north-west Australia.

Indospicine is a natural toxin occurring only in Indigofera plant species, including the Australian native species I. linnaei. These perennial legumes are resistant to drought and palatable to grazing livestock including cattle. Indospicine accumulates in the tissues (including muscle) of animals grazing Indigofera and these residues persist for several months after exposure. Dogs are particularly sensitive to indospicine with reports in past decades of hepatotoxicosis and mortalities in dogs after dietary exposure to indospicine-contaminated horse and camel meat. The risk for human consumption is not known, and the current study was undertaken to assess indospicine levels in cattle going to slaughter from divergent regions of Western Australia, and to predict the likelihood of significant residues being present. Muscle and corresponding liver samples from 776 cattle originating from the Kimberley and Pilbara Regions in the tropical north of the state, where I. linnaei is prevalent, and 640 cattle from the South West and South Coast Regions in the temperate south west of the state, where the plant is not known to occur, were collected at abattoirs over four seasons in 2015-2017. Indospicine levels were measured by LC-MS/MS and ranged from below detection to 3.63 mg/kg. No indospicine residues were detected in any of the animals originating from the South West and South Coast Regions. Prevalence of indospicine residues in cattle from the Kimberley Region was as high as 33% in spring and 91% in autumn, with positive animals being present in most consignments and on most properties. The average prevalence of indospicine residues from the Kimberley and Pilbara Regions throughout the survey period was 63%. @Risk best fit probability distributions showed ninety-fifth percentile (P95) indospicine concentrations of 0.54 mg/kg for muscle and 0.77 mg/kg for liver in cattle originating from the Kimberley and Pilbara Regions during the survey period. When considered with average Australian meat consumption data, the estimated consumer exposure from this P95 muscle was 0.32 µg indospicine/kg bw/day, which compared favourably with our calculated provisional tolerable daily intake (PTDI) of 1.3 µg indospicine/kg bw/day. However canine exposure is of potential concern, with active working dog exposure calculated to exceed this PTDI by a factor of 25, based on a P95 indospicine concentration of 0.54 mg/kg in muscle.

Release of Indospicine from Contaminated Camel Meat following Cooking and Simulated Gastrointestinal Digestion: Implications for Human Consumption.

Indospicine, a hepatotoxic arginine analog, occurs in leguminous plants of the Indigofera genus and accumulates in the tissues of grazing animals that consume these plants. Furthermore, indospicine has caused toxicity in dogs following consumption of indospicine-contaminated meat; however, the potential impact on human health is unknown. The present study was designed to determine the effect of simulated human gastrointestinal digestion on the release and degradation of indospicine from contaminated camel meat following microwave cooking. Results showed no significant (p > 0.05) indospicine degradation during cooking or in vitro digestion. However, approximately 70% indospicine was released from the meat matrix into the liquid digesta during the gastric phase (in the presence of pepsin) and increased to >90% in the intestinal phase (with pancreatic enzymes). Following human consumption of contaminated meat, this soluble and more bioaccessible fraction of intact indospicine could be readily available for absorption by the small intestine, potentially circulating indospicine throughout the human body to tissues where it could accumulate and cause detrimental toxic effects.

Quantitative structural organisation model for wheat endosperm cell walls: Cellulose as an important constituent.

The cell walls of cereal endosperms are a major source of fibre in many diets and of importance in seed structure and germination. Cell walls were isolated from both pure wheat endosperm and milled flour. 13C CP/MAS NMR in conjunction with methylation analysis before and after acid hydrolysis showed that, in addition to arabinoxylan (AX) and (1, 3; 1, 4)-ß-D-glucan (MLG), wheat endosperm cell walls contain a significant proportion of cellulose (ca 20%) which is tightly bound to xylans and mannans. Light microscopy showed that the cellulose was relatively evenly distributed across the grain endosperm. The cell walls contain a fibrous acid-resistant core structure laminated by matrix polysaccharides as revealed by AFM imaging. A model for endosperm cell wall structural organisation is proposed, based on a core of cellulose and interacting non-cellulosic polysaccharides which anchors AX (with very occasional diferulic acid cross-linking) that in turn retains MLGs through physical entanglement.

Buchanania obovata: Functionality and Phytochemical Profiling of the Australian Native Green Plum.

The green plum is the fruit of Buchanania obovata Engl. and is an Australian Indigenous bush food. Very little study has been done on the green plum, so this is an initial screening study of the functional properties and phytochemical profile found in the flesh and seed. The flesh was shown to have antimicrobial properties effective against gram negative (Escherichia coli 9001—NCTC) and gram positive (Staphylococcus aureus 6571—NCTC) bacteria. Scanning electron microscopy analysis shows that the antimicrobial activity causes cell wall disintegration and cytoplasmic leakage in both bacteria. Antioxidant 2,2-diphenyl-1-picrylhydrazyl (DPPH) testing shows the flesh has high radical scavenging activity (106.3 ± 28.6 μM Trolox equivalant/g Dry Weight in methanol). The flesh and seed contain a range of polyphenols including gallic acid, ellagic acid, p-coumaric acid, kaempferol, quercetin and trans-ferulic acid that may be responsible for this activity. The seed is eaten as a bush food and contains a delphinidin-based anthocyanin. The green plum has potential as a functional ingredient in food products for its antimicrobial and antioxidant activity, and further investigation into its bioactivity, chemical composition and potential applications in different food products is warranted.

LED power efficiency of biomass, fatty acid, and carotenoid production in Nannochloropsis microalgae.

The microalga Nannochloropsis produces high-value omega-3-rich fatty acids and carotenoids. In this study the effects of light intensity and wavelength on biomass, fatty acid, and carotenoid production with respect to light output efficiency were investigated. Similar biomass and fatty acid yields were obtained at high light intensity (150 µmol m-2 s-1) LEDs on day 7 and low light intensity (50 µmol m-2 s-1) LEDs on day 11 during cultivation, but the power efficiencies of biomass and fatty acid (specifically eicosapentaenoic acid) production were higher for low light intensity. Interestingly, low light intensity enhanced both, carotenoid power efficiency of carotenoid biosynthesis and yield. White LEDs were neither advantageous for biomass and fatty acid yields, nor the power efficiency of biomass, fatty acid, and carotenoid production. Noticeably, red LED resulted in the highest biomass and fatty acid power efficiency, suggesting that LEDs can be fine-tuned to grow Nannochloropsis algae more energy-efficiently.

Gene expression profiling of astaxanthin and fatty acid pathways in Haematococcus pluvialis in response to different LED lighting conditions.

Haematococcus pluvialis is a green microalga of major interest to industry based on its ability to produce large amounts of astaxanthin. Biosynthesis of astaxanthin and its mono- and di-esters was significantly stimulated under 150 µmol m-2 s-1 of white LED (W-150) compared with lower light intensities, but the highest astaxanthin amounts were produced under 70 µmol m-2 s-1 of blue LED (B-70). Transcripts of astaxanthin biosynthesis genes psy, crtO, and bkt2 were upregulated under W-150, while psy, lcy, crtO, and crtR-B were upregulated by B-70. Total fatty acid content and biosynthesis genes fata and all dgat genes were induced under W-150, while C18:3n6 biosynthesis and dgat2a expression were specifically stimulated by B-70 which was correlated to astaxanthin ester biosynthesis. Nitrogen starvation, various LEDs and the identified upregulated genes may provide useful tools for future metabolic engineering to significantly increase free astaxanthin, its esters and fatty acid precursors in H. pluvialis.

Pilot Study on Folate Bioavailability from a Camembert Cheese Reveals Contradictory Findings to Recent Results from a Human Short-term Study.

Different dietary sources of folate have differing bioavailabilities, which may affect their nutritional "value." In order to examine if these differences also occur within the same food products, a short-term human pilot study was undertaken as a follow-up study to a previously published human trial to evaluate the relative native folate bioavailabilities from low-fat Camembert cheese compared to pteroylmonoglutamic acid as the reference dose. Two healthy human subjects received the test foods in a randomized cross-over design separated by a 14-day equilibrium phase. Folate body pools were saturated with a pteroylmonoglutamic acid supplement before the first testing and between the testings. Folates in test foods and blood plasma were analyzed by stable isotope dilution assays. The biokinetic parameters C max, t max, and area under the curve (AUC) were determined in plasma within the interval of 0-12 h. When comparing the ratio estimates of AUC and C max for the different Camembert cheeses, a higher bioavailability was found for the low-fat Camembert assessed in the present study (≥64%) compared to a different brand in our previous investigation (8.8%). It is suggested that these differences may arise from the different folate distribution in the soft dough and firm rind as well as differing individual folate vitamer proportions. The results clearly underline the importance of the food matrix, even within the same type of food product, in terms of folate bioavailability. Moreover, our findings add to the increasing number of studies questioning the general assumption of 50% bioavailability as the rationale behind the definition of folate equivalents. However, more research is needed to better understand the interactions between individual folate vitamers and other food components and the potential impact on folate bioavailability and metabolism.

Folate bioavailability from foods rich in folates assessed in a short term human study using stable isotope dilution assays.

Different sources of folate may have different bioavailability and hence may impact the standard definition of folate equivalents. In order to examine this, a short term human study was undertaken to evaluate the relative native folate bioavailabilities from spinach, Camembert cheese and wheat germs compared to pteroylmonoglutamic acid as the reference dose. The study had a single-centre, randomised, four-treatment, four-period, four-sequence, cross-over design, i.e. the four (food) items to be tested (referred to as treatments) were administered in sequences according to the Latin square, so that each experimental treatment occurred only once within each sequence and once within each study period. Each of the 24 subjects received the four experimental items separated by a 14-day equilibrium phase and received a pteroylmonoglutamic acid supplement for 14 days before the first testing and between the testings for saturation of body pools. Folates in test foods, plasma and urine samples were determined by stable isotope dilution assays, and in urine and plasma, the concentrations of 5-methyltetrahydrofolate were evaluated. Standard non-compartmental methods were applied to determine the biokinetic parameters C(max), t(max) and AUC from baseline corrected 5-methyltetrahydrofolate concentrations within the interval from 0 to 12 hours. The variability of AUC and C(max) was moderate for spinach and oral solution of pteroylmonoglutamic acid but high for Camembert cheese and very high for wheat germs. The median t(max) was lowest for spinach, though t(max) showed a high variability among all treatments. When comparing the ratio estimates of AUC and C(max) for the different test foods, highest bioavailability was found for spinach followed by that for wheat germs and Camembert cheese. The results underline the dependence of folate bioavailability on the type of food ingested. Therefore, the general assumption of 50% bioavailability as the rationale behind the definition of folate equivalents has to be questioned and requires further investigation.

Binding of dietary polyphenols to cellulose: structural and nutritional aspects.

The interactions between polyphenols and plant fibres play an important role in controlling the release of phenolic compounds from food matrices for absorption in the gastrointestinal tract. This study probed the molecular interactions of diverse polyphenols with cellulose fibres by using a pure cellulose-producing bacterial model. Alkali treatment of bacterial cellulose was an effective method for obtaining a high purity cellulose model for study of polyphenol binding. Representatives of different polyphenol classes all bound to cellulose spontaneously, rapidly, and to comparable extents (up to 60% w/w of cellulose). Langmuir binding isotherms were applied to determine quantitative aspects of the adsorption at equilibrium. The study indicated that binding was similar on a molar basis for ferulic acid, gallic acid, catechin and cyanidin-3-glucoside (but lower for chlorogenic acid), with the native charge of polyphenols a secondary factor in the interactions between polyphenols and cellulose.

A randomized, double-blind, placebo-controlled trial of the effect of dried purple carrot on body mass, lipids, blood pressure, body composition, and inflammatory markers in overweight and obese adults: the QUENCH trial.

Obesity is a significant health issue worldwide and is associated with chronic, low-grade inflammation predisposing the individual to cardiovascular disease and impaired blood glucose homeostasis. Anthocyanins and phenolic acids from purple carrots are effective at reversing inflammation and metabolic alterations in animal models, potentially through inhibition of inflammatory pathways. The effects of dried purple carrot on body mass, body composition, blood pressure, lipids, inflammatory markers, liver function tests, and appetite were investigated in 16 males (aged 53.1 ± 7.6 years and with a mean BMI of 32.8 ± 4.6 kg/m(2)) with normal lipid and inflammatory markers. There was no evidence that 118.5 mg/day of anthocyanins and 259.2 mg/day of phenolic acids for 4 weeks resulted in statistically significant changes in body mass, body composition, appetite, dietary intake, low density lipoprotein, total cholesterol, blood pressure, or C-reactive protein in these obese participants at the dose and length of intervention used in this trial. High density lipoprotein cholesterol was lower in the intervention group (p < 0.05). Aspartate amino transferase and alanine amino transferase did not change, indicating that the intervention was safe. More studies are required to establish the bioavailability and pharmacokinetic effects of purple carrot anthocyanins and phenolic acids prior to further trials of efficacy with respect to treating inflammation and metabolic alterations.

Lack of release of bound anthocyanins and phenolic acids from carrot plant cell walls and model composites during simulated gastric and small intestinal digestion.

Separately, polyphenols and plant cell walls (PCW) are important contributors to the health benefits associated with fruits and vegetables. However, interactions with PCW which occur either during food preparation or mastication may affect bioaccessibility and hence bioavailability of polyphenols. Binding interactions between anthocyanins, phenolic acids (PAs) and PCW components, were evaluated using both a bacterial cellulose-pectin model system and a black carrot puree system. The majority of available polyphenols bound to PCW material with 60-70% of available anthocyanins and PAs respectively binding to black carrot puree PCW matter. Once bound, release of polyphenols using acidified methanol is low with only ∼20% of total anthocyanins to ∼30% of PAs being released. Less than 2% of bound polyphenol was released after in vitro gastric and small intestinal (S.I.) digestion for both the model system and the black carrot puree PCW matter. Confocal laser scanning microscopy shows localised binding of anthocyanins to PCW. Very similar patterns of binding for anthocyanins and PAs suggest that PAs form complexes with anthocyanins and polysaccharides. Time dependent changes in extractability with acidified methanol but not the total bound fraction suggests that initial non-specific deposition on cellulose surfaces is followed by rearrangement of the bound molecules. Minimal release of anthocyanins and PAs after simulated gastric and S.I. digestion indicates that polyphenols in fruits and vegetables which bind to the PCW will be transported to the colon where they would be expected to be released by the action of cell wall degrading bacteria.

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.