Chemical characterization of yellow-orange and purple varieties of Opuntia ficus-indica fruits and thermal stability of their betalains.

Betalains are plant pigments with biological properties and can be used instead of synthetic colorants to confer color and functional properties to foods. The objective of this work was to carry out the chemical characterization of two varieties of prickly pear of Opuntia ficus-indica, one of yellow-orange coloration (Mandarina) and the other of purple coloration (Vigor), through measurements of chemical parameters and color in pulp, antioxidant activity, total phenolic compounds, and betalain content. Considering the thermolability of betalains and their potential applications in food, the thermal stability and activation energy of betacyanins from Vigor variety and betaxanthins from the Mandarina variety were also evaluated and compared with those from beetroot, the main source of betalains. Results for chemical characterization agreed with previous prickly pear reports of other regions, while the thermal degradation kinetics of betalains showed a first-order degradation pattern with respect to time and temperature treatment. Betacyanins from Vigor prickly pear showed similar thermal stability to those from beetroot, which was reflected in similar values of activation energy, while betaxanthins from Mandarina prickly pear showed a higher stability, and therefore a higher activation energy, than those from beetroot. Based on the results, the prickly pear varieties used in this study can be considered as a good source of betalains with potential applications in food and, in addition, the methodology for the evaluation of thermostability can be used to compare the stability of betalains from different sources in a temperature range of 50-90°C. PRACTICAL APPLICATION: The varieties of prickly pear used in this study can be considered a good source of red-purple and yellow-orange easily extractable pigments. In addition, we report a methodology that can be used for the evaluation of the thermal stability of these pigments and to compare this stability between different plant sources. Gaining knowledge on betalain thermal stability will make it possible to propose specific applications, for example, in processed foods requiring different pigment stabilities.

Extraction of Lipophilic Antioxidants from Native Tomato Using Green Technologies.

Research background: Tomato (Solanum lycopersicum L.) fruit is highly consumed worldwide and contains high amounts of carotenoids and tocopherols, two powerful antioxidants. Native tomato genotypes are rarely used in large-scale market but serve as a reservoir to diversify the species gene pool and can be employed to obtain functional compounds. Extraction methods are currently changing towards cleaner procedures that are more efficient and environmentally friendly, including avoiding toxic or polluting solvents. Experimental approach: In this study, factorial and fractional factorial designs were used to evaluate the efficiency of digestive enzymes, sonication and green solvents to obtain lipophilic antioxidant extracts from native tomato. To monitor the efficiency of the extraction process, spectrophotometric quantification of total carotenoids and antioxidant activity was carried out, and then individual quantification of carotenoids and tocopherols in the extracts was done by HPLC. Results and conclusions: Digestive enzymes and sonication increased the carotenoid content and the antioxidant activity of the obtained extracts when applied individually. However, when these treatments were applied together and in combination with isopropyl acetate, a green solvent, the obtained extracts had the highest carotenoid and tocopherol contents as well as the maximal antioxidant activity. A correlation analysis suggested that antioxidant activity resulted from synergistic effects rather than individual compounds. Tomato extracts were obtained through a rapid and environmentally friendly extraction method and their antioxidant activity was enhanced. Novelty and scientific contribution: Tomato fruits have been the subject of numerous studies; however, functional compound extraction through environmentally friendly methods remains an attractive use of native tomato fruit, enhancing its limited production and harnessing a large amount of tomato product industry. There are few reports where environmentally friendly extraction methods are combined; even rarer are those where green solvents are also used. In this work, the combination of different environmentally friendly extraction methods improved the extraction of carotenoids and tocopherols and allowed to establish a more efficient process. These results could stimulate the use of clean technologies and make the native tomato more attractive for industrial or compound extraction processes.

Betalain plant sources, biosynthesis, extraction, stability enhancement methods, bioactivity, and applications.

Betalains are plant pigments with functional properties used mainly as food dyes. However, they have been shown to be unstable to different environmental factors. This paper provides a review of (1) Betalain plant sources within several plant families such as Amaranthaceae, Basellaceae, Cactaceae, Portulacaceae, and Nyctaginaceae, (2) The biosynthesis pathway of betalains for both betacyanins and betaxanthins, (3) Betalain extraction process, including non-conventional technologies like microwave-assisted, ultrasound-assisted, and pulsed electrical field extraction, (4) Factors affecting their stability, mainly temperature, water activity, light incidence, as well as oxygen concentration, metals, and the presence of antioxidants, as well as activation energy as a mean to assess stability, and novel food-processing technologies able to prevent betalain degradation, (5) Methods to increase shelf life, mainly encapsulation by spray drying, freeze-drying, double emulsions, ionic gelation, nanoliposomes, hydrogels, co-crystallization, and unexplored methods such as complex coacervation and electrospraying, (6) Biological properties of betalains such as their antioxidant, hepatoprotective, antitumoral, and anti-inflammatory activities, among others, and (7) Applications in foods and other products such as cosmetics, textiles and solar cells, among others. Additionally, study perspectives for further research are provided for each section.

Environmentally friendly achiote seed extracts with higher δ-tocotrienol content have higher in vitro and in vivo antioxidant activity than the conventional extract.

Achiote (Bixa orellana) is highly appreciated as a condiment and as the main source of bixin and tocotrienols, both having antioxidant properties. To explore the possibility of maximizing the antioxidant activity of achiote seed extracts using clean methodologies, the use of sonication and green solvents were tested. Ethyl lactate, isopropyl acetate, and ethanol combined with probe sonication produced the best results, obtaining similar bixin contents but higher δ-tocotrienol contents, as well as significantly higher in vitro and in vivo antioxidant activity compared with the maceration method extract, requiring low energy and saving time and solvents. The probe-sonicated achiote extract with the highest δ-tocotrienol content was better at increasing the Caenorhabditis elegans resistance to oxidative stress than the extract obtained through maceration. This is the first report about the effect of sonication combined with green solvents on the bixin and δ-tocotrienol content in achiote seed extracts and its relevance on the in vitro and in vivo antioxidant activity.

Achiote (Bixa orellana) Lipophilic Extract, Bixin, and δ-tocotrienol Effects on Lifespan and Stress Resistance in Caenorhabditis elegans.

The onset of many degenerative diseases related to aging has been associated with a decrease in the activity of antistress systems, and pharmacological interventions increasing stress resistance could be effective to prevent the development of such diseases. Achiote is a valuable source of carotenoid and tocotrienols, which have antioxidant activity. In this work, we explore the capacity of an achiote seed extract and its main compounds to modulate the lifespan and antistress responses on Caenorhabditis elegans, as well as the mechanisms involved in these effects. Achiote lipophilic extract, bixin, and δ-tocotrienol were applied on nematodes to carry out lifespan, stress resistance, and fertility assays. The achiote seed extract increased the median and maximum lifespan up to 35% and 27% and increased resistance against oxidative and thermal stresses without adverse effects on fertility. The beneficial effects were mimicked by a bixin+δ-tocotrienol mixture. All the effects on lifespan and stress resistance were independent of caloric restriction but dependent on the insulin/insulin growth factor-1 pathway. This study could provide insights for further research on a new beneficial use of this important crop in health and nutraceutical applications beyond its use as a source of natural pigments.

Some naturally occurring compounds that increase longevity and stress resistance in model organisms of aging.

Humans and other organisms show age-related signs of deterioration, which makes aging an interesting process to study. In the present work, we review the anti-aging evidence of several of the most promising natural compounds. Quercetin, rapamycin, resveratrol, spermidine, curcumin or sulforaphane administration increase longevity and stress resistance in model organisms such as yeasts, nematodes, flies and mice. Even more, rapamycin, resveratrol, and curcumin are currently in preclinical tests on the Interventions Testing Program of the National Institute on Aging due to their encouraging results in model organisms. The potential mechanisms underlying the beneficial effects of these compounds are briefly described.