Rheological Flow Behavior of Structural Polysaccharides from Edible Tender Cladodes of Wild, Semidomesticated and Cultivated 'Nopal' (Opuntia) of Mexican Highlands

Blends of Cactus Cladode Powder with Corn Starch, Milk Proteins and Gelatin: Rheological Evaluation and Application to a Soup Model

Cactus cladodes (Opuntia ficus-indica) is a valuable source of dietary fibers. In this study, peeled cladode powder was produced by air drying at 40 °C and was characterized for its color, dietary fiber content, and rheological behavior. Cladode powder aqueous suspensions of 3% w/w were prepared and the effect of protein (gelatin, sodium caseinate, and whey protein) or salts (NaCl/CaCl2) on the blend’s viscosity was investigated. Additionally, cladode powder was incorporated in a soup model, aiming at substituting corn starch. Our powder had an appealing green color, but its deterioration was fast when it was exposed to light. A shear-thinning behavior was observed in all cladode-protein mixtures, but viscosity values depended considerably on the protein type and the pH values. Notably, gelatin addition led to higher apparent viscosity of cladode powder at pH 6, suggesting interactions with cladode mucilage, but this effect was reversed at pH 4, below gelatin isoelectric point. The Ostwald-de Waele model successfully correlated viscosity-shear rates data, whereas the Casson model presented a good fit mainly in starch containing systems. Corn starch substitution by cladode powder, in the soup model, led to lower consistency coefficient values. In soups, the logarithmic mixing law was applied at different corn starch: cladode powder ratios to highlight their possible interactions. The values obtained diverged slightly downwards from the logarithmic mixing law. When purified mucilage was added—instead of cladode powder—the samples diverged slightly upwards from the logarithmic mixing law.

Cladodes: Chemical and structural properties, biological activity, and polyphenols profile

The nopal cactus is an essential part of the Mexican diet and culture. The per capita consumption of young cladodes averages annually to 6.4 kg across the nation. In addition to contributing to the country's food culture, the nopal is considered a food with functional characteristics since, in addition to providing fiber, an important group of polyphenolic compounds is present, which has given cladodes to be considered a healthy food, for what they have been incorporated into the diet of Mexican people and many other countries worldwide. Research suggests that polyphenols from cladodes act as antioxidants and antidiabetics. This review studies the main phenolic components in cladodes and summarizes both conventional and novel methods to identify them.

Sopa de elote (Zea mays) tipo crema con mucílago de nopal (Opuntia spp.) como espesante, sus características físicas y aceptación sensorial

El mucílago de nopal (Opuntia spp.) es un polisacárido calificado como nutracéutico por sus efectos positivos en la fisiología de los humanos. Por otro lado, el mucílago puede usarse como espesante, ya que al hidratarse forma hidrocoloides. El objetivo de este estudio fue adicionar mucílago de nopal a la sopa de elote tipo crema y evaluar su efecto espesante y aceptación sensorial. El mucílago se extrajo de cladodios de Opuntia spp. de las variantesAtlixco, Milpa Alta, Toluca, Tobarito y Tuna Blanca. Las concentraciones evaluadas fueron 0.7 y 1.0% y se incluyó almidón como testigo. Con algunas excepciones, la sopa de los 10 tratamientos con mucílago mostró pH (entre 6.09 y 6.32) y viscosidad (entre 6.043 y 1.623 Pa s) sin diferencias significativas (p > 0.05) respecto a los testigos; además, mostró la misma saturación (entre 17.47º y 18.49º), mayor luminosidad (entre 46.15 y 47.72º) y menos color (entre 78.36 y 79.52º). La aceptabilidad sensorial por viscosidad, excepto con mucílago de Atlixco y de Toluca (17 y 7% menor, respectivamente), y la aceptabilidad sensorial global con el mucílago, de las cinco variantes fue hasta 19% menor que la de los testigos. Tendrá que ponderarse el beneficio de adicionar mucílago de nopal a la sopa de elote, para usarse como alimento funcional, sobre su aceptabilidad global.

Identificación de propiedades presentes en jugo de Opuntia megacantha Salm-Dyck importantes para la producción de biopolímeros

Con el objetivo de identificar las propiedades químicas y los antioxidantes de interés en la industria de los biopolímeros se realizó la caracterización química del jugo de cuatro variantes de cladodios de Opuntia megacantha; las variantes presentan dos grados de madurez (tiernos y maduros) y dos manejos diferentes durante su desarrollo (silvestres y cultivados). El grado de madurez de los cladodios fue estadísticamente significativo (p ≤ 0.05), el jugo de los cladodios maduros presentó mayor cantidad de fibra cruda y material libre de nitrógeno, el jugo de cladodios tiernos contiene mayor cantidad de proteína, extracto etéreo y cenizas. No existió diferencia estadística significativa (p = 0.6917), en el contenido de los fenoles en las cuatro variantes se obtuvieron concentraciones entre 165.6 y 176.6 mg GAE/mL; (2.18 y 3.61 mg GAE/g en peso seco). Los jugos de los cladodios maduros contienen mayor cantidad de los diferentes azúcares cuantificados (p ≤ 0.05). Se prepararon películas de biopolímero utilizando jugo clarificado de cladodios silvestres tiernos para determinar su resistencia a la tensión con un resultado de 1.42 MPa, módulo de Young de 1.77 MPa y elongación a la rotura de 124.16%; se concluye que los jugos caracterizados en este trabajo pueden ofrecer una alternativa viable a los polímeros derivados del petróleo.

The Comparative Effect of Nopal and Mucilage in Metabolic Parameters in Rats with a High-Fructose Diet

Nopal is used in Mexico as both food and traditional medicine for metabolic diseases. Our aim was to analyze the effect of the chronic administration of mucilage fiber extracted from nopal (Opuntia ficus indica; 500 mg/kg body weight per day) on male Wistar rats on a high-fructose diet (HFD). After which three groups were administered one of the following for 30 days: whole-fresh nopal mixed in water, mucilage, and control. Metabolic and hemodynamic parameters (triglycerides, cholesterol, fasting glucose, oral glucose tolerance test, blood pressure, and abdominal circumference) were determined. Rats administered nopal and mucilage had lower levels of triglycerides and diastolic arterial pressure than control, but only nopal had significant differences. Furthermore, systolic and diastolic pressure were higher in the control group. Thus, whole nopal and mucilage improve metabolic parameters in rats fed a HFD.

A dietary intervention with functional foods reduces metabolic endotoxaemia and attenuates biochemical abnormalities by modifying faecal microbiota in people with type 2 diabetes

AIM

To study the effects of a functional food-based dietary intervention on faecal microbiota and biochemical parameters in patients with type 2 diabetes (T2D).

MATERIALS AND METHODS

This placebo-controlled, randomized, double-blind study included 81 patients with T2D divided into two 3-month treatment groups: one following a reduced-energy diet with a dietary portfolio (DP) comprising high-fibre, polyphenol-rich and vegetable-protein functional foods; the other taking a placebo (P). The primary outcome was the effect of the DP on faecal microbiota. Secondary endpoints were biochemical parameters, lipopolysaccharide, branched-chain amino acids, trimethylamine N-oxide, glycosylated haemoglobin (HbA_1c) and free fatty acids (FFAs).

RESULTS

Patients with T2D exhibited intestinal dysbiosis characterized by an increase in Prevotella copri. Dietary intervention with functional foods significantly modified faecal microbiota compared with P by increasing alpha diversity and modifying the abundance of specific bacteria, independently of antidiabetic drugs. There was a decrease in P. copri and increases in Faecalibacterium prausnitzii and Akkermansia muciniphila, two bacterial species known to have anti-inflammatory effects. The DP group also exhibited significant reductions in areas under the curve for glucose, total and LDL cholesterol, FFAs, HbA_1c (P< 0.05), triglycerides and CRP, and an increase in antioxidant activity (P< 0.01) vs. the P group.

CONCLUSION

Long-term adherence to a high-fibre, polyphenol-enriched and vegetable-protein-based diet provides benefits for the composition of faecal microbiota, and may offer potential therapies for improvement of glycaemic control, dyslipidaemia and inflammation.