Excessive adipose accumulation, which is the main driver for the development of secondary metabolic complications, has reached epidemic proportions and combined pharmaceutical, educational and nutritional approaches are required to reverse the current rise in global obesity prevalence rates. Brown adipose tissue (BAT) is a unique organ able to dissipate energy and thus a promising target to enhance BMR to counteract a positive energy balance. In addition, active BAT might support body weight maintenance after weight loss to prevent/reduce relapse. Natural products deliver valuable bioactive compounds that have historically helped to alleviate disease symptoms. Interest in recent years has focused on identifying nutritional constituents that are able to induce BAT activity and thereby enhance energy expenditure. This review provides a summary of selected dietary phytochemicals, including isoflavones, catechins, stilbenes, the flavonoids quercetin, luteolin and resveratrol as well as the alkaloids berberine and capsaicin. Most of the discussed phytochemicals act through distinct molecular pathways e.g. sympathetic nerve activation, AMP-kinase signalling, SIRT1 activity or stimulation of oestrogen receptors. Thus, it might be possible to utilise this multitude of pathways to co-activate BAT using a fine-tuned combination of foods or combined nutritional supplements.

Piglets are characteristically cold intolerant and thus susceptible to high mortality. However, browning of white adipose tissue (WAT) can induce non-shivering thermogenesis as a potential strategy to facilitate the animal’s response to cold. Whether cold exposure can induce browning of subcutaneous WAT (sWAT) in piglets in a similar manner as it can in humans remains largely unknown. In this study, piglets were exposed to acute cold (4°C, 10 h) or chronic cold exposure (8°C, 15 days), and the genes and proteins of uncoupling protein 1 (UCP1)-dependent and independent thermogenesis, mitochondrial biogenesis, lipogenic and lipolytic processes were analysed. Interestingly, acute cold exposure induced browning of porcine sWAT, smaller adipocytes and the upregulated expression of UCP1, PGC1α, PGC1β, C/EBPβ, Cidea, UCP3, CKMT1 and PM20D1. Conversely, chronic cold exposure impaired the browning process, reduced mitochondrial numbers and the expression of browning markers, including UCP1, PGC1α and PRDM16. The present study demonstrated that acute cold exposure (but not chronic cold exposure) induces porcine sWAT browning. Thus, browning of porcine sWAT could be a novel strategy to balance the body temperature of piglets, and thus could be protective against cold exposure.

Introduction. The fruit of Averrhoa carambola L., or carambola, is an attractive tropical fruit of the Oxalidaceae family. As most of the carambola crop is consumed fresh, very few carambolas are processed. However, the high variability in fruit quality produced by Caribbean countries is a major limitation to market penetration. Processing of carambolas could allow the utilization of low quality fruits, which cannot be marketed, to reduce waste, improve on the economic returns of farmers and increase the value of the crop. Our work thus aimed at studying carambola wine quality in relation to certain treatments applied before the fermentation of the must. Materials and methods. Pectolase was added to the pasteurized carambola pulp to the concentrations of (0, 0.1, 0.2 and 0.3)%. Another treatment used pectolase to 0.3% with addition of 1% of citric acid and 0.25% of ascorbic acid and associated with the use of various yeast strains of Saccharomyces cerevisiae from various wines (Super, Chablis and Sweet Mead). The must was adjusted to 25 °Brix and pH 3.0–3.5. The carambola wine quality obtained at the end of each treatment was assessed using physicochemical characteristics and sensory evaluations. Results and discussion. Addition of pectolase improved the carambola wine’s light transmittance, sensory color, sensory clarity and overall acceptability. Addition of 1% citric acid and 0.25% ascorbic acid to the must resulted in less dark and yellow wines with a more acceptable color. Wines fermented with the Chablis yeast strain had the highest clarity (88.55% of light transmittance). The wines were microbiologically stable. Conclusion. Carambola wine treated with 0.3% pectolase with the inclusion of 1% citric acid and 0.25% ascorbic acid with different yeast strains had (7.35 to 7.65) °Brix, (10.25 to 11.50)% alcohol, pH 3.01 to 3.02, (79.20 to 88.55)% of light transmittance and (17.50 to 17.76) mg ascorbic acid·100 mL–1. These wines had overall acceptability rating from slightly to moderately liked and they were judged as superior.

Introduction. The peel of lychee fruit turns from its attractive bright red color to a dull brown color when the fruit starts to age. This study reports how the color change of lychee pericarp from red to brown is associated with several factors and may be reversed depending on its pH, anthocyanin content and brown pigments. Materials and methods. After transport by air transit from China to Canada, arriving 4 d after harvest, the anthocyanin, brown pigment concentrations and the pH values in the lychee (Litchi chinensis Sonn.) pericarp were determined over a period of 5 d at 25 °C and 65% RH. The macromolecular sizes of the brown pigment extract were measured in solutions between a pH of 4 and 6. Results and discussion. The acidity in the lychee pericarp decreased from a pH of 4.3 to 5.3, at the end of the 5-day period. The anthocyanins in the lychee pericarp decreased and the brown pigment increased. Polyphenol oxidase in the pericarp was active when its pH was between 4.1 and 4.6, and became less active when its pH was above 4.6. The diameter of the brown pigment molecules in the solutions increased when the pH of the solutions was increased and maintained for 5 d. The anthocyanins returned to their original redness and concentrations if they were placed in solutions with a pH value ranging between 4 and 6 for 10 min or they were placed in solutions with a pH value of 4 for 5 d. However, the anthocyanins did not return to their original redness and concentration if they were placed in solutions with a pH value ranging between 5 and 6 for 5 d. Conclusion. This study suggests that the bright red color of lychee peel could be maintained if its pericarp pH could be maintained at a pH of 4. If the pericarp pH is above 4, the reversibility of its bright red color from brown pigments is dependent on storage time.

Experimental Camembert cheeses were made to investigate the effects on browning of the following factors: inoculation with Yarrowia lipolytica, the use of Penicillium candidum strains with different proteolytic activity, the addition of tyrosine, and the addition of Mn2+, thus leading to 16 different variants of cheese. Two physical colour parameters were used to describe browning, depending on the location in the cheeses: a whiteness index for the outside browning (mould mycelium), and a brownness index for the inside browning (surface of the cheese body). Mn2+ promoted a significant increase of browning at both locations, whereas Yar. lipolytica had the opposite effect. Outside browning was significantly more intense when using the Pen. candidum strain with higher proteolytic activity. A significant interaction was found between Yar. lipolytica and Pen. candidum. The yeast had no effect in combination with a low proteolytic strain of Pen. candidum, but significantly reduced proteolysis and browning in combination with a high proteolytic strain of Pen. candidum. We further confirmed that both strains of Pen. candidum were able to produce brown pigments from tyrosine, and thus both are presumably responsible for the browning activity in this type of cheese.