Relationship between weather conditions and the physicochemical characteristics of cladodes and mucilage from two cactus pear species

Abstract

Climate change, limited water resources and expected population increases would require crops which contribute toward more resilient, more productive, more sustainable and climate-smart food systems. The cactus pear is a drought-resistant and sustainable food source to humans and livestock alike. Cactus mucilage has multiple applications in the food and packaging industry. It is eco-friendly, economical, functional and has multiple health benefits. However, the researchers observed umpteen variations in extracted mucilage yield and viscosity every time the cladodes were harvested, making the standardisation of formulations troublesome. We aimed to examine the effect of weather conditions on the physicochemical characteristics of cactus pear cladodes and mucilage extracted over two seasons to understand these observed variations in mucilage characteristics. Forty cladodes, ten from each of Opuntia ficus-indica Algerian, Morado and Gymno-Carpo and Opuntia robusta Robusta were harvested every month from February to August in Bloemfontein, South Africa. Daily weather data were obtained, weight and moisture contents determined on cladodes and yield, viscosity, pH, conductivity and malic acid content determined on extracted mucilage. Pearson correlation coefficients were calculated between the weather conditions, cladode properties, and mucilage properties. Contrary to common belief, neither increasing cladode weight as they grow, nor rainfall were the leading causes of mucilage inconsistencies. However, the correlations showed a relationship between environmental temperatures, cladode pH and conductivity, and mucilage viscosity and yields. In hot summer weather, the pH was lower, which led to an abundance of positive ions in cladodes. The H+ ions neutralise the negative charges along the outstretched mucilage molecule, causing it to coil up, reducing the viscosity of the mucilage. Thus, environmental temperatures rather than rainfall or cladode maturity influenced the physicochemical characteristics of mucilage. The findings should make an essential contribution in predicting the physicochemical

Comparative Analysis of the Chemical Composition and Physicochemical Properties of the Mucilage Extracted from Fresh and Dehydrated Opuntia ficus indica Cladodes

“…Evidently, the difference in the viscosity of the FNM and the DNM will have a significant impact on the textural properties of the products to which these mucilages are added. For example, the FNM can be used in products where a moderate or low viscosity is needed to replace dairy or fats (e.g., frozen desserts) and to make edible coatings and films on minimally processed products [71,72]. In contrast, the DNM can be useful to improve textural characteristics of products and to replace egg and fats (e.g., dressings) [71].…”

“…For example, the FNM can be used in products where a moderate or low viscosity is needed to replace dairy or fats (e.g., frozen desserts) and to make edible coatings and films on minimally processed products [71,72]. In contrast, the DNM can be useful to improve textural characteristics of products and to replace egg and fats (e.g., dressings) [71].…”

Influence of age on molecular characteristics and rheological behavior of nopal mucilage

“…The selection and collection of the cladodes was random from different plants. Since, the climate, temperature, and harvesting time of the cladodes may affect the physical–chemical properties of the mucilages and their rheological behavior in solution (Du Toit et al., 2020 ), the cladodes were harvested in just one season, that is, during the spring in Morelos, in the months of March and April, systematically early in the morning (at 6:00 a.m.) when the average temperature is around 12°C. The cladodes were harvested by weight, namely, 4 kg of each type, which resulted in 58 ± 1, 28 ± 1, and 16 ± 2 pieces of T , Y , and M cladodes, respectively.…”

“…The mucilage from nopal is water soluble and has the capacity to form viscoelastic solutions and gels, depending on its molecular weight and concentration. Therefore, this polysaccharide is often considered as a hydrocolloid with potential applications as thickener (Bernardino‐Nicanor et al., 2015 ), as a functional ingredient in foods (Dick et al., 2020 ; Du Toit et al., 2019 ), as well as an emulsion stabilizer in the cosmetic and pharmaceutical industries (Du Toit et al., 2020 ; Quinzio et al., 2018 ). In addition, nopal mucilages have been used in the preparation of biodegradable packings and coatings to increase the shelf life of vegetables and fruits (Allegra et al., 2017 ; Gheribi et al., 2018 ), meanwhile as the elastic properties of their solutions (film forming capabilities) are well known, nopal mucilages are often used as binders in rustic paints.…”

Characterization of mucilage from clones of Opuntia and Nopalea prickly pear cactus harvested in different seasons in Brazilian semiarid

“…The vast majority of studies on prickly pear cactus mucilage and its applications in the food industry have been conducted with species of the genus Opuntia . Du Toit et al (2020) is the most recent research on the physicochemical characterization of mucilage according to climatic conditions. In addition, cultivars and harvest months of the year also influence the quality of mucilage and its technological properties (Du Toit et al, 2020;Du Toit et al, 2018) However, the cactus used was typical of South Africa, genus Opuntia.…”