Production and characterization of solid lipid microparticles loaded with guaraná (Paullinia cupana) seed extract.

Guaraná is a native fruit of the Amazon rainforest, which presents high levels of phenolic compounds. However, these bioactive compounds may be unstable in food processing and gastrointestinal conditions. Thus, this work aimed to characterize guaraná seed extract (GSE) followed by microencapsulation using a spray-chilling method and with vegetable fat as carrier, as well as to evaluate the particles. Phenolic-rich GSE was produced using 50% (w/w) hydroalcoholic solution and dehydrated by spray drying and lyophilization. Powdered GSE was characterized in relation to its inhibitory activity on digestive enzymes. Solid lipid microparticles (SLM) were evaluated for the retention of bioactive compounds and the release profile of phenolic compounds in simulated gastrointestinal conditions. Powdered GSE showed anti-obesity potential due to the high inhibitory activity of lipase. Regarding the retention of phenolic compounds, at least 75% were detected after 90 days at 25 °C in SLM. Moreover, SLM loaded with 7.5% GSE released approximately 99% of phenolic compounds in simulated gastrointestinal conditions. These results show the efficiency of spray chilling for protection and release of phenolic compounds from GSE, allowing future application in food.

Evaluation of the release profile, stability and antioxidant activity of a proanthocyanidin-rich cinnamon (Cinnamomum zeylanicum) extract co-encapsulated with α-tocopherol by spray chilling.

Cinnamon has many health improving compounds such as proanthocyanidins, which also have potential for the prevention of damages caused by diabetes. Similarly, α-tocopherol is a natural antioxidant with important role on protection of fatty acids in membranes and lipoproteins. However, the addition of antioxidants in food may result in interaction with food matrix, low stability and unpleasant taste. In the present study, a proanthocyanidin-rich cinnamon extract (PRCE) (Cinnamomum zeylanicum) was co-encapsulated with α-tocopherol into solid lipid microparticles (SLMs) by spray chilling. The microparticles were characterized with regard to the physical and chemical properties, morphology, proanthocyanidin stability and release profile. SLMs were spherical with an average diameter of ca. 80µm. Proanthocyanidins were highly stable in SLMs stored for up to 90days at 5, 25 and 37°C. Moreover, SLMs gradually released proanthocyanidins in simulated gastrointestinal fluids by a diffusional process, following a Korsmeyer-Peppas kinetic. Analyses of the antioxidant compounds indicated that PRCE components exhibited a higher scavenging capacity against reactive oxygen species (ROS) and reactive nitrogen species (RNS). Thus, the SLMs produced in the present study have potential for application in the development of new functional foods and nutraceuticals, also providing an alternative for the controlled release of proanthocyanidins and α-tocopherol into the intestine.

Flavonoids, proanthocyanidins, vitamin C, and antioxidant activity of Theobroma grandiflorum (Cupuassu) pulp and seeds.

The ascorbic acid, flavonoids, and proanthocyanidins content and in vitro antioxidant activity of fresh pulps and seeds of cupuassu, harvested at three different times of the year, and in commercial frozen pulps were evaluated. Lipids, total phenolics contents, and antioxidant activities were the highest in the seeds, followed by fresh and commercial frozen pulps, respectively. The latter also showed a lower content of ascorbic acid (9-13 mg/100 g DW) when compared to fresh pulps (96-111 mg/100 g DW). The 8-O-ß-D-glucuronides and the corresponding 3″-sulfates of isoscutellarein (5,7,8,4'-tetrahydroxyflavone), hypolaetin (5,7,8,3',4'-pentahydroxyflavone), and 8-hydroxychrysoeriol (5,7,8,4'-tetrahydroxy-3'-methoxyflavone), also known as hypoaletin 3'-methyl ether, were identified and quantified (31 mg/g DW) in cupuassu seeds. The same flavonoid profile was present in pulps although in much lower concentrations (0.5 to 2 mg/g DW). The two 8-hydroxychrysoeriol glycosides had not been previously reported in cupuasssu. The content of proanthocyanidin oligomers in seeds (23 mg/g DW), mainly of the epicatechin type, and the mean degree of polymerization (5.5) were calculated. No discernible effect of the harvesting period on the evaluated chemical aspects could be identified. Commercial frozen pulps contained a smaller amount of all these compounds than the fresh pulp, suggesting that these compounds were potentially degraded during processing/storage.

Bioactive compounds and phenolic-linked functionality of powdered tropical fruit residues.

Tropical fruit residues consisting of seeds, peels and residual pulp generated as by-products of fruit processing industry were investigated for bioactive compounds, the in vitro antioxidant capacity as well as alpha-glucosidase and alpha-amylase inhibitory activities. Cyanidin, quercetin, ellagic acid (EA) and proanthocyanidins were found in acerola, jambolan, pitanga and cajá-umbu residue powders. Acerola powder had the highest phenolic content (8839.33 mg catechin equivalents (CE)/100 g) and also high-ascorbic acid (AA) concentration (2748.03 mg/100 g), followed by jambolan and pitanga. The greatest 1,1-Diphenyl-2-picrylhydrazyl (DPPH) inhibition was observed for jambolan (436.76 mmol Trolox eq/g) followed by pitanga (206.68 mmol Trolox eq/g) and acerola (192.60 mmol Trolox eq/g), while acerola had the highest ferric reducing antioxidant power (FRAP) assay result (7.87 mmol Trolox eq/g). All fruit powders exhibited enzymatic inhibition against alpha-amylase (IC50 ranging from 3.40 to 49.5 mg CE/mL) and alpha-glucosidase (IC50 ranging from 1.15 to 2.37 mg CE/mL). Therefore, acerola, jambolan and pitanga dried residues are promising natural ingredients for food and nutraceutical manufacturers, due to their rich bioactive compound content.

Effect of free or protein-associated soy isoflavones on the antioxidant status in rats.

BACKGROUND: The objective of this study was to investigate the effect of chronic ingestion of free and protein-associated soy isoflavones on the antioxidant status in male Wistar rats. Free isoflavone (iso), protein-associated soy isoflavone (iso + prot) and soy protein (prot) extracts were administered for 30 days by gavage to the rats at a dosage of 1 mg aglycone isoflavones per 200 g body weight, adjusted daily, and the prot group was given the same concentration of soy protein received by the iso + prot group. Antioxidant capacity of plasma, thiobarbituric acid-reactive substance (TBARS) and glutathione (GSH) levels and catalase (CAT), glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities in plasma, erythrocytes and tissues and gene expression levels in liver and kidney were evaluated. RESULTS: Chronic ingestion of free but not of protein-associated soy isoflavones nor of solely soy protein increased plasma antioxidant capacity and GPx activity in erythrocytes. Soy protein increased CAT activity and gene expression in liver. SOD activity in erythrocytes was increased by all treatments. CONCLUSION: The overall results confirm that dietary soy isoflavones have a positive effect on antioxidant status, enhancing antioxidant capacity of plasma and antioxidant enzymes in various tissues, but the effects are dependent on the form of administration and on a complex mechanism of antioxidant status balance on the organism.