Açai (Euterpe oleracea)
Dr. Steve Talcott
Texas A&M University
Pacheco-Palencia, L., Talcott, S.T. 2010. Chemical stability of açai fruit (Euterpe oleracea Mart.) anthocyanins as influenced by naturally occurring and externally added polyphenolic cofactors in model systems. Food Chemistry, 118, 17-25.
Pacheco-Palencia, L., Talcott, S.M., Talcott, S.T. 2010. In-vitro Absorption and Antiproliferative Activities of Monomeric and Polymeric Anthocyanin Fractions from Açai Fruit (Euterpe oleracea Mart.). J. Agric. Food Chem, 119, 1071-1078.
Pacheco-Palencia, L., Duncan, C.E., Talcott, S.T. 2009. Phytochemical Composition and Thermal Stability of Two Commercial Açai Species, Euterpe oleracea and Euterpe precatoria. Food Chemistry, 115, 1199-1205.
See our interview on ABC News Nightline on March 26, 2010
Like I said in the interview "We have just seen the tip of the iceberg" when it comes to açai.
Background on Açai
Açai (Euterpe oleracea Mart.) is a palm plant widely distributed in northern South America with its greatest occurrence and economic importance in the floodplains of the Brazilian Amazon. Açai is a slender, multi-stemmed, monoecious palm that can reach a height of over 30 meters. A wide variety of marketable products are produced from this palm, but the spherical fruits that are mainly harvested from July to December are its most important edible product. Each palm tree produces from 3 to 4 bunches of fruit, each bunch having from 3-6 kg of fruit. The round-shaped fruits appear in green clusters when immature and ripen to a dark, purple colored fruit that ranges from 1.0-1.5 cm in diameter. The seed accounts for most of the fruit size and is covered by thin fibrous fibers under which is a small edible layer. A viscous juice is typically prepared by macerating the edible pulp that is approximately 2.4% protein and 5.9% lipid. The juice is currently used to produce energetic snack beverages, ice cream, jelly, liqueur, and is commonly blended with a variety of other juices.
Comparing Two (2) Commercial Species of Acai
Phytochemical Composition and Thermal Stability of Two Commercial Açai Species, Euterpe oleracea and Euterpe precatoria. Lisbeth A. Pacheco-Palencia, Christopher E. Duncan, and Stephen T. Talcott. Food Chemistry (in press)
Açai fruit are native to the Amazon region of South America and two predominant species are commercially exported as fruit pulps for use in food and beverage applications. Detailed characterization of the polyphenolic compounds present in the de-seeded fruits of E. oleracea and E. precatoria species were conducted by HPLC-ESI-MSn analyses and their thermal stability and overall influence on antioxidant capacity determined. Anthocyanins were the predominant polyphenolics in both Euterpe oleracea (2,247 ± 23 mg/kg) and E. precatoria (3,458 ± 16 mg/kg) species, and accounted for nearly 90% of the Trolox equivalent antioxidant capacity in both E. oleracea (87.4 ± 4.4 μmol TE/g) and E. precatoria (114 ± 6.9 μmol TE/g) fruits. Various flavones, including homoorientin, orientin, taxifolin deoxyhexose, and isovitexin; flavanol derivatives, including (+)-catechin, (-)-epicatechin, procyanidin dimers and trimers; and phenolic acids, including protocatechuic, p-hydroxybenzoic, vanillic, syringic, and ferulic acid, were also present in both species. Thermal stability of these compounds was evaluated following a thermal holding cycle (80ºC for up to 60 min) in the presence and absence of oxygen. Both species experienced only minor changes (<5%) in non-anthocyanin polyphenolic contents during all thermal processes whereas 34 ± 2.3% of anthocyanins in E. oleracea and 10.3 ± 1.1% of anthocyanins in E. precatoria were lost under these conditions, regardless of the presence of oxygen. Proportional decreases (10 to 25%) in antioxidant capacity accompanied the anthocyanin changes. Results suggest both açai species are characterized by similar polyphenolic profiles, comparable antioxidant capacities, yet only moderate phytochemical stability during heating.
Açai Human Consumption Trial: Bioavailability of Anthocyanins
Pharmacokinetics of Anthocyanins and Antioxidant Effects after the Consumption of Anthocyanin-Rich Acai Juice and Pulp (Euterpe oleracea Mart.) in Human Healthy Volunteers. Mertens-Talcott, S.M., Rios, J., Jilma-Stohlawetz, P., Pacheco-Palencia, L., Beibohm, B., Talcott, S. T., Derendorf, H. 2008. Journal of Agricultural and Food Chemistry 56; 7796-7802.
The açai berry is the fruit of the acai palm and is traditionally consumed in Brazil but has gained popularity abroad as a food and functional ingredient, yet little information exists on its health effect in humans. This study was performed as an acute four-way crossover clinical trial with açai pulp and clarified açai juice compared to applesauce and a non-antioxidant beverage as controls. Healthy volunteers (12) were dosed at 7 mL/kg of body weight after a washout phase and overnight fast, and plasma was repeatedly sampled over 12 h and urine over 24 h after consumption. Noncompartmental pharmacokinetic analysis of total anthocyanins quantified as cyanidin-3-O-glucoside showed Cmax values of 2321 and 1138 ng/L at tmax times of 2.2 and 2.0 h, and AUC last values of 8568 and 3314 ng h L-1 for pulp and juice, respectively. Nonlinear mixed effect modeling identified dose volume as a significant predictor of relative oral bioavailability in a negative nonlinear relationship for açai pulp and juice. Plasma antioxidant capacity was significantly increased by the açai pulp and applesauce. Individual increases in plasma antioxidant capacity of up to 2.3- and 3-fold for açai juice and pulp, respectively were observed. The antioxidant capacity in urine, generation of reactive oxygen species, and uric acid concentrations in plasma were not significantly altered by the treatments. Results demonstrate the absorption and antioxidant effects of anthocyanins in açai in plasma in an acute human consumption trial.
Absorption of Antioxidants from Açai Pulp and Açai Oil
Absorption and Biological Activity of Phytochemical-Rich Extracts from Açai (Euterpe oleracea Mart.) Pulp and Oil in Vitro. Pacheco-Palencia, Talcott, S.T., Safe, S., Mertens-Talcott, S.M. 2008. Journal of Agricultural and Food Chemistry, 56, 3593-3600.
Polyphenolic extracts from various fruits and vegetables have been shown to exert growth inhibitory effects in cell culture studies. Whereas individual polyphenolic compounds have been extensively evaluated, understanding of the biological activity of polyphenolic extracts from natural sources is limited and critical to the understanding of their potential effects on the human body. This study investigated the absorption and antiproliferative effects of phytochemical extracts from ac¸ai pulp and a polyphenolic-enriched ac¸ai oil obtained from the fruit pulp of the ac¸ai berry (Euterpe oleracea Mart.). Chemical composition, antioxidant properties, and polyphenolic absorption of phytochemical fractions in a Caco-2 monolayer were determined, along with their cytotoxicity in HT-29 human colon adenocarcinoma cells. Standardized extracts were characterized by their predominance of hydroxybenzoic
acids, monomeric flavan-3-ols, and procyanidin dimers and trimers. Polyphenolic mixtures (0-12 μg of gallic acid equiv/mL) from both açai pulp and açai oil extracts inhibited cell proliferation by up to 90.7%, which was accompanied by an increase of up to 2.1-fold in reactive oxygen species. Absorption experiments using a Caco-2 intestinal cell monolayer demonstrated that phenolic acids such as p-hydroxybenzoic, vanillic, syringic, and ferulic acids, in the presence of DMSO, were readily transported from the apical to the basolateral side along with monomeric flavanols such as (+)-catechin and (-)-epicatechin. Results from this study provide further evidence for the bioactiveproperties of açai polyphenolics and offer new insight on their composition and cellular absorption.
Chemical Composition and Thermal Stability of Antioxidants from Acai Pulp and Acai Oil
Antioxidant Properties, and Thermal Stability of a Phytochemical Enriched
Oil from Acai Açai (Euterpe oleracea Mart.). P
Phenolic compounds present in crude oil extracts from açai fruit (Euterpe oleracea) were identified for the first time. The stability of açai oil that contained three concentrations of phenolics was evaluated under short- and long-term storage for lipid oxidation and phenolic retention impacting antioxidant capacity. Similar to açai fruit itself, açai oil isolates contained phenolic acids such as vanillic acid (1,616 94 mg/kg), syringic acid (1,073 62 mg/kg), p-hydroxybenzoic acid (892 52 mg/kg), protocatechuic acid (630 36 mg/kg), and ferulic acid (101 5.9 mg/kg) at highly enriched concentrations in relation to açai pulp as well as (+)-catechin (66.7 4.8 mg/kg) and numerous procyanidin oligomers (3,102 130 mg/kg). Phenolic acids experienced up to 16% loss after 10 weeks of storage at 20 or 30 °C and up to 33% loss at 40 °C. Procyanidin oligomers degraded more extensively (23% at 20 °C, 39% at 30 °C, and 74% at 40 °C), in both high- and low-phenolic açai oils. The hydrophilic antioxidant capacity of açai oil isolates with the highest phenolic concentration was 21.5 1.7 µmol Trolox equivalents/g, and the total soluble phenolic content was 1252 11 mg gallic acid equivalents/kg, and each decreased by up to 30 and 40%, respectively, during long-term storage. The short-term heating stability at 150 and 170 °C for up to 20 min exhibited only minor losses (<10%) in phenolics and antioxidant capacity. Because of its high phenolic content, the phytochemical-enriched açai oil from açai fruit offers a promising alternative to traditional tropical oils for food, supplements, and cosmetic applications.
Processing Stability of Acai
Pacheco-Palencia L., Hawkin, P., Talcott, S.T. 2007. Phytochemical, antioxidant and pigment stability of açai (Euterpe oleracea Mart.) as affected by clarification, ascorbic acid fortification and storage. Food Research International, 40, 620-628.
Açai juice at two clarity stages (semi-clarified and clarified) was compared to 100% açai pulp following ascorbic acid fortification to evaluate phytochemical and antioxidant changes during storage at 4 and 20 °C. Cyanidin-3-rutinoside (202 ± 5.8mg/L) and cyanidin-3-glucoside (75 ± 4.8mg/L) were the predominant anthocyanins in açai while 11 non-anthocyanin polyphenolics were detected in concentrations from 1.1 to 55 mg/L of açai pulp. Clarification of açai pulp resulted in a 27% loss in total polyphenolics (197 ± 6.9 mg gallic acid/100mL) and in a 20% reduction in both total anthocyanins (729 ± 3.4 mg/L) and antioxidant capacity (54 ± 1.7 μmol Trolox equivalents/mL). Anthocyanin degradation followed first order kinetics, with half-lives ranging from 9.4 to 43 days for cyanidin-3-glucoside and from 18 to 82 days for cyanidin-3-rutinoside. Fortification with ascorbic acid accelerated anthocyanin degradation in clarified juice at both storage temperatures, likely due to the loss of polymeric anthocyanin forms (21%) during clarification. Although clarification enhanced the amount of monomeric anthocyanins present in açai juice which relates positively to the aesthetic quality, processing and handling regimes must be optimized to achieve maximum retention of their functional properties during storage.
Ascorbic Acid Fortification of Acai (Good or Bad?)
Pacheco-Palencia, L., Hawkin, P., Talcott, S.T. 2007. Juice matrix composition and ascorbic acid fortification effects on the phytochemical, antioxidant and pigment stability of açai (Euterpe oleracea Mart.) In press, Food Chemistry, web release date: March 20, 2007.
The effects of juice matrix composition on the phytochemical stability of açai (Euterpe oleracea Mart.) were evaluated by contrasting natural clarified juice systems with isolated polyphenolic and anthocyanin fractions, in the presence or absence of ascorbic acid (500 mg/L) under accelerated storage conditions (37ºC). Polyphenolic (anthocyanin and non-anthocyanin polyphenolics) and anthocyanin fractions were isolated using C18 Sep-Pak columns and then re-dissolved in the original aqueous juice matrix (unbound fraction) or in a citric acid buffer (pH 3.5). The isolation of anthocyanins from the açai matrix improved their color stability but a greater retention of non-anthocyanin polyphenolics and antioxidant properties were favored by the initial juice composition. The presence of non-anthocyanin polyphenolics exerted a protective effect against ascorbic acid oxidation and enhanced polyphenolic and antioxidant stability in isolates fortified with ascorbic acid. However, all isolates obtained from açai experienced significant color, polyphenolic, and antioxidant losses during storage and indicated that optimization of early stages of industrial processing, storage, and distribution are necessary to retain the functional properties of açai-containing products.
Health Benefits of Açai
Del Pozo-Insfran, D., Percival, S.S., Talcott, S.T. 2006. Acai (Euterpe oleracea Mart.) polyphenolics in their glycosidic and alycone forms induce apopotsis of HL-60 luekemia cells. J. Agric. Food Chem. 54, 1222-1229.
Consistent evidence supports an association between consumption of fruits and vegetables rich in polyphenolics with decreased incidence of certain cancers. Acai, a palm fruit native to South America, was previously determined to contain a diversity of polyphenolics with high antioxidant capacity, yet its bioactive properties have not been investigated. The effects of açai polyphenolics (0-10.7 µM) on the antiproliferation and induction of apoptosis in HL-60 human leukemia cells was investigated. Specific interactions between anthocyanins and polyphenolics in both glycosidic and aglycone forms were investigated to determine additive or synergistic responses. Predominant polyphenolics in açai included cyanidin, ferulic acid, epicatechin, p-hydroxy benzoic acid (1,040, 212, 129, 80.5 mg/L, respectively). Catechin, gallic, protocatechuic, and free ellagic acid were also identified (ca. 60mg/L). Polyphenolic fractions at 10.7 µM were found to reduce cell proliferation up to 86%, and were similar among the isolates except for the isolated polyphenolics (<58%). Polyphenolic and anthocyanin fractions were non-additive in their contribution to the cell anti-proliferation activity with respect to the C18-retained total polyphenolic isolate. Generally at equimolar concentrations, the glycosidic forms induced a higher magnitude of change in vital cell parameters (proliferation and apoptosis) than their respective aglycone forms. This study demonstrated that açai offers a rich source of bioactive polyphenolics with apoptotic activity that also reduced cell proliferation in a model system for cancer.
Phytochemistry of Açai
Del Pozo-Insfran, D., Brenes, C.H., Talcott, S.T. 2004. Phytochemical Composition and Pigment Stability of Açai (Euterpe oleracea Mart.). Journal of Agricultural and Food Chemistry, 52, 1539-1545.
Anthocyanin and polyphenolic compounds present in açai (Euterpe oleracea Mart.) were determined and their respective contribution to the overall antioxidant capacity established. Color stability of açai anthocyanins against hydrogen peroxide (0 and 30 mmol/L) over a range of temperatures (10-30 °C) was also determined and compared to common anthocyanin sources. Additionally, stability in a model beverage system was evaluated in the presence of ascorbic acid and naturally occurring polyphenolic cofactors. Cyanidin 3-glucoside (1,040 mg/L) was the predominant anthocyanin in açai and correlated to antioxidant content, while 16 other polyphenolics were detected from 4-212 mg/L. Red grape anthocyanins were most stable in the presence of hydrogen peroxide, while açai and pigments rich in acylated anthocyanins displayed lower color stability in a temperature-dependent manner. In the presence of ascorbic acid, acylated anthocyanin sources generally had increased color stability. Açai was recognized for its functional properties for use in food and nutraceutical products.
Açai Press Release
BRAZILIAN BERRY DESTROYS CANCER CELLS IN LAB, UF STUDY SHOWS
Jan. 12, 2006 / Story and photo available at http://news.ufl.edu/2006/01/12/berries/
GAINESVILLE, Fla. --- A Brazilian berry popular in health food contains antioxidants that destroyed cultured human cancer cells in a recent University of Florida study, one of the first to investigate the fruit’s purported benefits.
Published today in the Journal of Agricultural and Food Chemistry, the study showed extracts from acai (ah-SAH’-ee) berries triggered a self-destruct response in up to 86 percent of leukemia cells tested, said Stephen Talcott, an assistant professor with UF’s Institute of Food and Agricultural Sciences.
“Acai berries are already considered one of the richest fruit sources of antioxidants,” Talcott said. “This study was an important step toward learning what people may gain from using beverages, dietary supplements or other products made with the berries.”
He cautioned that the study, funded by UF sources, was not intended to show whether compounds found in acai berries could prevent leukemia in people.
“This was only a cell-culture model and we don’t want to give anyone false hope,” Talcott said. “We are encouraged by the findings, however. Compounds that show good activity against cancer cells in a model system are most likely to have beneficial effects in our bodies.”
Other fruits, including grapes, guavas and mangoes, contain antioxidants shown to kill cancer cells in similar studies, he said. Experts are uncertain how much effect antioxidants have on cancer cells in the human body, because factors such as nutrient absorption, metabolism and the influence of other biochemical processes may influence the antioxidants’ chemical activity.
Another UF study, slated to conclude in 2006, will investigate the effects of acai’s antioxidants on healthy human subjects, Talcott said. The study will determine how well the compounds are absorbed into the blood, and how they may affect blood pressure, cholesterol levels and related health indicators. So far, only fundamental research has been done on acai berries, which contain at least 50 to 75 as-yet unidentified compounds.
“One reason so little is known about acai berries is that they’re perishable and are traditionally used immediately after picking,” he said. “Products made with processed acai berries have only been available for about five years, so researchers in many parts of the world have had little or no opportunity to study them.”
Talcott said UF is one of the first institutions outside Brazil with personnel studying acai berries. Besides Talcott, UF’s acai research team includes Susan Percival, a professor with the food science and human nutrition department, David Del Pozo-Insfran, a doctoral student with the department and Susanne Mertens-Talcott, a postdoctoral associate with the pharmaceutics department of UF’s College of Pharmacy.
Acai berries are produced by a palm tree known scientifically as Euterpe oleracea, common in floodplain areas of the Amazon River, Talcott said. When ripe, the berries are dark purple and about the size of a blueberry. They contain a thin layer of edible pulp surrounding a large seed.
Historically, Brazilians have used acai berries to treat digestive disorders and skin conditions, he said. Current marketing efforts by retail merchants and Internet businesses suggest acai products can help consumers lose weight, lower cholesterol and gain energy.
“A lot of claims are being made, but most of them haven’t been tested scientifically,” Talcott said. “We are just beginning to understand the complexity of the acai berry and its health-promoting effects.”
In the current UF study, six different chemical extracts were made from acai fruit pulp, and each extract was prepared in seven concentrations.
Four of the extracts were shown to kill significant numbers of leukemia cells when applied for 24 hours. Depending on the extract and concentration, anywhere from about 35 percent to 86 percent of the cells died.
The UF study demonstrates that research on foods not commonly consumed in the United States is important, because it may lead to unexpected discoveries, said Joshua Bomser, an assistant professor of molecular nutrition and functional foods at The Ohio State University in Columbus, Ohio.
But familiar produce items have plenty of health-giving qualities, he said.
“Increased consumption of fruits and vegetables is associated with decreased risk for many diseases, including heart disease and cancer,” said Bomser, who researches the effects of diet on chronic diseases. “Getting at least five servings a day of these items is still a good recommendation for promoting optimal health.”