Polysaccharides of nutritional interest in jicama (Pachyrhizus erosus) during root development

Tuber crops could be a potential food component for lowering starch digestibility and estimated glycemic index in rice

BACKGROUND

Rice is considered a high estimated glycemic index (eGI) food because of its higher starch digestibility, which leads to type II diabetes and obesity as a result of a sedentary life style. Furthermore, the incresaing diabetes cases in rice-consuming populations worldwide need alternative methods to reduce the glycemic impact of rice, with dietary prescriptions based on the eGI value of food being an attractive and practical concept. Rice is often paired with vegetables, pulses, tubers and roots, a staple food group in Africa, Latin America and Asia, which are rich in fibre and health-promoting compounds.

RESULTS

Rice from four categories (high protein, scented, general and pigmented) was analyzed for eGI and resistant starch (RS) content. Among the genotypes, Improved Lalat had the lowest eGI (53.12) with a relatively higher RS content (2.17%), whereas Hue showed the lowest RS (0.19%) with the highest eGI (76.3) value. The addition of tuber crops to rice caused a significant lowering of eGI where the maximum beneficial effect was shown by elephant foot yam (49.37) followed by yam bean (53.07) and taro (54.43).

CONCLUSION

The present study suggests that combining rice with suitable tuber crops can significantly reduce its eGI value, potentially reducing the burden of diet-associated lifestyle diseases particularly diabetics. © 2024 Society of Chemical Industry.

Health-Related Composition and Bioactivity of an Agave Sap/Prickly Pear Juice Beverage

In this study, a beverage made from a combination of Agave sap (AS) and prickly pear juice (PPJ) was analyzed for its nutrients and bioactive and potentially health-promoting compounds. The beverage was evaluated for its ability to act as an antioxidant, regulate glycemic properties, and undergo gut bacterial fermentation in vitro. The major mono- and oligosaccharides present in the beverage were galacturonic acid (217.74 ± 13.46 mg/100 mL), rhamnose (227.00 ± 1.58 mg/100 mL), and fructose (158.16 ± 8.86 mg/mL). The main phenolic compounds identified were protocatechuic acid (440.31 ± 3.06 mg/100 mL) and catechin (359.72 ± 7.56 mg/100 mL). It was observed that the beverage had a low glycemic index (<40) and could inhibit digestive carbohydrases. The combination of ingredients also helped to reduce gas production during AS fermentation from 56.77 cm3 to 15.67 cm3. The major SCFAs produced during fermentation were butyrate, acetate, and propionate, with valerate being produced only during the late fermentation of the AS. This beverage is rich in bioactive compounds, such as polyphenols and dietary fiber, which will bring health benefits when consumed.

Nanomechanical, Structural and Antioxidant Characterization of Nixtamalized Popcorn Pericarp

Expanded popcorn grain is widely consumed as a healthy snack all around the world; however, the study of the behavior of its components by processes such as nixtamalization is scarce. Therefore, the aim of this work was to characterize the nanomechanical, structural, and antioxidant properties of nixtamalized popcorn grain pericarp. FT-IR results showed that the secondary structure of proteins of the nixtamalized pericarp was α-helix with 42.10%, the turn was 21.5% and 36.33% β-sheet, and proteins of the pericarp did not present the random coil structure. Pericarp showed antioxidant activity, as their values were 550.1 ± 2.9 and 44.2 ± 1.6 (TE)/mL for ABTS and DPPH, respectively; total phenols content was 0.21 ± 0.008 (TE)/mL; reducing power values were around 29 to 31%; hydroxyl radical scavenging ranged from 36 to 55% and iron chelation around 115 to 140% compared to the standard acids. Thickness values of the nixtamalized pericarp by SEM image analysis were 0.15 ± 0.1 mm near the pedicel inferior tip, 0.07 ± 0.01 mm at middle, and 0.03 ± 0.02 mm at upper of the grain. Young’s modulus value was 261.72 ± 23.58 MPa with a Gaussian function fitting at the distribution of all values. This research provides novel and valuable information for understanding the nanomechanical and protein arrangement, as well as and the antioxidant activity of nixtamalized popcorn grain pericarp in order to promote other processes and uses for this kind of pericarp maize.

Polysaccharides of nutritional interest in jicama (Pachyrhizus erosus) during root development

Jicama root applications have focused on their nutraceutical properties without clearly specifying which compounds are related to this effect. Thus, the aim of the present study was to identify the changes in polysaccharides of nutraceutical interest in two commercial jicama roots (YS – Yellow Seed; PS – Purple Seed) during four stages of maturation, focusing on starch, fructooligosaccharides, and pectin (via galacturonic acid), and on their glycemic index, with the goal of determining, if possible, the best cost‐effectiveness between jicama growing stages and nutraceutical effect. Both materials (YS, PS) presented similar growth rates (0.069 and 0.072 cm/day) and final sizes (12.7 ± 1.25, 12.3 ± 1.63 cm). Changes in size were accompanied by changes in protein, fiber, ashes, lipids, and carbohydrates, after 106 or 127 days of growing. It was also found that fructose content was higher than glucose during the maturing stages, possibly because of the hydrolysis of fructooligosaccharides or sucrose for starch production. Concerning inulin, its levels decreased (<6.0%), after the first days (YS: 13.4% ± 0.7%; PS: 8.4% ± 0.2%, 106 days); however, during development, the presence of other fructooligosaccharides was observed (nystose‐YS 106 days 15.8% ± 0.9% and PS‐106 days 18.5% ± 0.1%), while galacturonic acid and native starch levels increased, which must be related to the jicama's low glycemic index found (<25%), and their nutraceutical properties. This work proves the presence of inulin in jicama roots by analytical methods, its dependence on root development and classifies jicama as a low glycemic index food, supporting its nutraceutical character.