A Systematic Review on Opuntia (Cactaceae; Opuntioideae) Flower-Visiting Insects in the World with Emphasis on Mexico: Implications for Biodiversity Conservation

Opuntia spp. are cacti with high ecological, economic and conservation interest in semiarid environments, particularly in Mexico. We conducted a systematic search of the existing peer-reviewed literature about the state of knowledge of pollination ecology on these plants. We documented the most studied Opuntia species worldwide with an emphasis on Mexico. We found that only 15% of Opuntia species described have been investigated so far, and studies were mainly focused on comprehension of the biology of a single species. Despite the economic and cultural importance of Opuntia, there is a significant lack of knowledge about the flower-visiting insects and their taxonomic identity. We provide a checklist of the insect species associated with Opuntia spp. Through a circular network, we visualize the complex Opuntia flower-visiting insect relationship, and we detected a set of key species constituting the generalist core of the networks constructed. Since pollination is crucial for crop production, a better understanding of ecological interactions would inform management measures to strengthen biodiversity and agriculture sustainability as well as productivity in arid and marginal lands. Further research on pollination ecology is needed to improve the conservation status of the insects associated with Opuntia species.

Productividad de forraje de variedades de nopal (Opuntia spp.) bajo diferentes regímenes de humedad del suelo

El objetivo de este estudio fue evaluar el crecimiento y producción de biomasa de variedades de nopal en diferentes contenidos de humedad del suelo como alternativa de producción forrajera. Se usó un diseño experimental de bloques al azar en un arreglo de parcelas divididas con tres repeticiones. Las parcelas grandes fueron los contenidos de humedad edáfica: muy favorable (22 - 27%), favorable (16 - 21%) y desfavorable (10 - 15%); las parcelas chicas correspondieron a las variedades de nopal: Chapingo (Ch) Narro (N) y Escobar (E). La variedad Chapingo fue estadísticamente mayor (P < ó = 0.05) en ancho y grosor de cladodios en los contenidos de humedad del suelo favorable y muy favorable, con valores de 15.7 y 1.1 cm y 15.2 y 1.0 cm, respectivamente; las variedades Escobar y Narro fueron las que registraron mayor contenido relativo de agua (CRA) en los contenidos de humedad favorable y desfavorable, con valores de 78.1 y 63%, respectivamente. El índice de clorofila no varió por efecto de ninguno de los factores variación probados en este estudio. La variedad Narro fuela de mejor productividad en el contenido más favorable de humedad del suelo, con valores de 1.77 Kg y 173.5 g de biomasa fresca y seca por planta, equivalente a 11.8 y 1.15 t ha-1 de biomasa fresca y seca, respectivamente, en corte de cladodios después de ocho meses de realizado el trasplante.

Agave and Opuntia Species as Sustainable Feedstocks for Bioenergy and Byproducts

Currently, Mexico is facing an energy transition, therefore updated policy regulations pertaining to the sustainable use of biomass are needed. In particular, policy that favors the sustainable use of biomass to produce energy and bioproducts to privilege climate change mitigation is needed. This review describes the use of maguey (Agave spp.) and nopal (Opuntia spp.; also known as “cactus”) for biofuel production, especially in marginal areas. Emphasis is given on documented case studies discussing features of production and cultivation for both maguey and nopal, in addition to their potential for fuel production. Environmental and social sustainability issues in terms of waste value and new opportunities as bioenergy feedstocks and byproducts are also discussed. Although the paper does not deeply describe aspects of biomass transformation, such as bioprocess configurations, it gives characteristics of production in addition to cultivation. Agave and Opuntia species may represent a suitable feedstock for biofuels, bioproducts, bioenergy and biorefineries, especially in dry lands (semi-arid and dry sub-humid), deforested areas, agroforestry systems and agricultural semi-terraces known as metepantle in Mexico.

Bioactive Compounds of Opuntia spp. Acid Fruits: Micro and Nano-Emulsified Extracts and Applications in Nutraceutical Foods

The acid fruit of the "xoconostle" cactus belongs to the genus Opuntia family of cacti. It is used as a functional food for its bioactive compounds. Several studies reported that xoconostle fruits have a high amount of ascorbic acid, betalains, phenols, tannins, and flavonoids. These compounds confer antioxidant, antibacterial, anti-inflammatory, and hepatoprotective gastroprotective activity. Xoconostle fruit extracts were tested by in vitro assays where the digestion conditions were simulated to measure their stability. At the same time, the extracts were protected by encapsulation (microencapsulation, multiple emulsions, and nanoemulsions). Applications of encapsulated extracts were probed in various food matrices (edible films, meat products, dairy, and fruit coatings). The xoconostle is a natural source of nutraceutical compounds, and the use of this fruit in the new food could help improve consumers’ health.

Comparative Assessment of Physical and Chemical Characteristics of Prickly Pear Seed Oil from Opuntia ficus-indica and Opuntia megacantha Varieties

The prickly pear (Opuntia spp.) is an important plant in the economies of arid and semiarid areas, considering its low agronomic requirements and high water use efficiency. Characterizing the chemical composition of this plant will open new avenues for food, pharmaceutical, and cosmetic applications. In this context, this study examined the physical and chemical parameters of fruit seed oils of two prickly pear species from Rhamna area located in the center of Morocco: Opuntia ficus-indica (OFI), represented by the varieties “Safra” and “Aakria,” and Opuntia megacantha (OM), represented by the variety “Derbana.” The evaluated parameters included oil content, free acidity, specific extinction coefficients (K232 and K270), pigment content, fatty acid, and triglyceride composition. The seed oil contents of the three varieties “Safra,” “Aakria,” and “Derbana” were 8.09%, 8.74%, and 8.04%, respectively. OM (“Derbana”) seed oil was the most stable. The three studied varieties had higher contents of α-pheophytin and carotenoids than that of chlorophyll. Oil from the “Aakria” variety was distinguished by having the highest contents of α-pheophytin and chlorophyll. Significant differences in some fatty acid and triglyceride contents were noted. The major fatty acids of the three varieties were linoleic acid (60.55%–63.46%), followed by oleic acid (18.88%–21.81%) and palmitic acid (13.03%–13.75%). Furthermore, the chromatographic profiles of the triglycerides have shown the dominance of trilinolein (LLL, 24.33%–26.49%) and oleoyl-dilinoleoyl-glycerol (OLL, 20.92%–21.92%). Some triglycerides could be considered species markers, especially OLL, dipalmitoyl-linoleoyl-glycerol (PPL), oleoyl-linoleoyl-linolenoyl-glycerol and palmitoyl-oleoyl-dilinoleoyl-glycerol fraction (OLLn + PoLL), and stearoyl-dioleoyl-glycerol (SOO). This study provides a basis for qualitatively evaluating the therapeutic and cosmetic potential of prickly pear derivatives and for establishing quality standards of seed oil derived from the two species studied.

In Vitro Antioxidant Capacity of Opuntia spp. Fruits Measured by the LOX-FL Method and its High Sensitivity Towards Betalains

Current in vitro methodologies neglect or subestimate the contribution of betalains to antioxidant capacity in foods because they do not reflect their in vivo biological mechanisms. In this study, we assessed the sensibility of the lipoxygenase-fluorescein (LOX-FL) method towards betalains, phenolic compounds and ascorbic acid from Opuntia spp. fruits; and (ii) the antioxidant capacity of peel and pulp extracts from Opuntia ficus-indica L. Mill (var. Fresa, Colorada and Blanco) and Opuntia stricta var. Dillenii; by comparing the LOX-FL method to traditional antioxidant methods (ORAC and TEAC). The spectrophotometric monitoring of the LOX-FL reaction avoided interference caused by betalain pigments. Indicaxanthin and betanin showed high antiperoxidative and radical scavenging mechanisms in the LOX-FL assay. O. stricta var. Dillenii tissues the highest antioxidant capacity which correlated with betanin content. ORAC and TEAC antioxidant methods were less sensible towards betalain antioxidant activity. To our knowledge, this is the first time the LOX-FL antioxidant method has been used on betalains and betalain-rich foods. Graphical Abstract

Efecto del nopal (Opuntia spp) deshidratado en polvo en las propiedades fisicoquímicas, texturales y sensoriales de salchichas Viena

Los cladodios de nopal (Opuntia spp) contienen fibra dietética, un ingrediente clave en la formulación de alimentos funcionales, su presentación comercial en polvo deshidratado lo hace apto para el procesamiento de alimentos. En este estudio se analizaron los cambios fisicoquímicos y sensoriales de pastas cárnicas de salchichas Viena adicionadas con 0 % (TNOP0), 2 % (TNOP2), 4 % (TNOP4) y 6 % (TNOP6) de nopal deshidratado en polvo. Posterior a las 24 h de la elaboración se calcularon las pérdidas por cocción; al día 7 se analizaron la composición nutrimental (humedad, proteína, extracto etéreo, cenizas y fibra cruda), la capacidad de retención de agua, el color, el perfil instrumental de textura y el análisis sensorial. A mayor incorporación de nopal deshidratado el perfil nutrimental de las salchichas mejora al reducir el porcentaje de grasa y aumentar el de fibra cruda (p < 0.05); existe una tendencia de coloración amarilla y un oscurecimiento a mayor incorporación de nopal (p < 0.05); la textura de las pastas con 6% de nopal se ve modificada negativamente; la aceptación global de la salchicha disminuye al incrementar el contenido de fibra, aunque el tratamiento al 2 % muestra una aceptación comparable con el tratamiento control.

Opuntia spp. Fibre Characterisation to Obtain Sustainable Materials in the Composites Field

Some studies have evaluated the use of Opuntia as reinforcement for polymeric matrices, obtaining good results in energy absorption tests and increasing the tensile elastic modulus. However, no studies focusing on the previous characterisation of the fibres and their treatment to improve compatibility with polymeric matrices have been found. This work analyses the chemical composition of Opuntia maxima (OM) and Opuntia dillenii (OD) cladodes and fibre, studying how different treatments influence it. AOAC 2000 methods were used to determine non-structural components and the Van Soest method was used to estimate structural components. Surface characteristics of the samples were also evaluated by Fourier Transform Infrared Spectroscopy (FTIR). Opuntia fibre presented higher cellulose (50–66%) and lignin (6–14%) content and lower hemicellulose (8–13%) content than Opuntia cladodes (9–14% cellulose, 20–50% hemicellulose, 1–4% lignin). Despite the variability of lignocellulosic materials, OD cladodes treated with water and acetic acid achieved an increase in the structural components. Alkaline fibre treatment removed pectin and hemicellulose from the fibre surface, slightly increasing the cellulose content. Future research should evaluate whether the treated Opuntia fibre can improve the mechanical properties of reinforced polymer.