Effects of concentrations, temperature, pH and co-solutes on the rheological properties of mucilage from Dioscorea opposita Thunb. and its antioxidant activity

Rheological property and thermodynamic parameters of Ficus carica Linn. pectin: A natural low-methoxyl pectin (LMP) with excellent pseudoplasticity

With the annual increase in the production of fig fruit (Ficus carica Linn.) in China, the processing and utilization of its by-products have become an important topic in fig research. In this study, a new type of natural low-methoxyl pectin (LMP) was obtained from figs by acid extraction (DE = 44.42 %). Fig pectin was an acidic heteropolysaccharide with a molecular weight of 75.9 kDa, and it was composed of galacturonic acid (248.09 mg/g), and neutral sugars including galactose (15.37 mg/g), arabinose (13.23 mg/g), rhamnose (6.74 mg/g), glucuronic acid (6.27 mg/g), xylose (0.78 mg/g), and fucose (0.26 mg/g). Shear-thinning behavior was shown at the concentration between 20 g/L - 60 g/L and the temperature between 5 °C - 50 °C of pectin solution, power law rheology model was used to describe the flow behavior of pectin solution. The apparent viscosity of pectin gradually raised with increasing concentration (at 25 °C, K is from 39.72 to 4140.39 Pa·sn, and n is from 0.85 to 0.42) and decreasing temperature (at 50 g/L, K is from 2233.55 to 17,549.48 Pa·sn, and n is from 0.37 to 0.47). Interestingly, pseudoplastic behavior was observed in all samples. Pectin solution exhibited thixotropic behavior, through the hysteresis loop through an up-down cycle in the shear rate-shear stress curve. The elastic modulus (G') and viscous modulus (G") of the pectin gradually reduced with decreasing concentration (20 g/L - 60 g/L) and increasing temperature (5°C - 50°C). Pectin exhibited a transition from elasticity (G' > G") to viscosity (G' < G") at higher concentration. The thermal degradation of pectin was mainly divided into three stages at different heating rate (5, 10, 15, 20 K-1). With the increasing of the heating rate, melt temperature (Tm) (240.66 °C - 250.69 °C) and enthalpy change (ΔH) (28.65 J/g - 90.43 J/g) increased. These results enriched understanding of the rheological property and thermodynamic parameters of fig pectin and were conducive to expanding the application of fig pectin in food processing.

A comparative study on utilization of different plant-derived nano-mucilage as a fat replacer in yogurt: Product optimization, physicochemical attributes, shelf-life evaluation, and consumer perception with market orientation

This study aimed to utilize different plant-derived mucilage as a fat substitute in yogurt production. Colocasia esculenta rhizome mucilage (CEM), Cordia dichotoma fruit mucilage (CDM), and Psyllium husk mucilage (PHM) were extracted using different extraction process, and spray dried to acquire nano-scaled mucilage particles (100-300 nm). Seven different types of yogurts were prepared with the addition of varied mucilage concentrations (1-10 % w/v). Results showed that the yogurt with 4.5 % PHM exhibited suitable viscosity, higher water holding capacity, and reduced syneresis over the 16 days of storage. Furthermore, selected yogurt sample revealed similar physicochemical, textural, and color attributes as compared to control (full-fat and skimmed-milk yogurt). Moreover, this study showed that consumers highly accepted mucilage-formulated yogurt, with a mean score of 97.16 ± 1.58 %. Overall, nano-mucilage holds potential as a sustainable biomaterial for producing low-fat yogurt.

Purple Yampee Derivatives and Byproduct Characterization for Food Applications

This study assessed the technological potential and bioactive compounds present in purple yampee (Dioscorea trifida L.f.) lyophilized powder, peeled and whole flour, as well as the tuber peel, starch residual fiber, and wastewater mucilage. Although most values approached neutrality, flour showed a lower pH and high density, while greater acidity was observed in the mucilage. Color differed statistically and perceptibly between all samples, with similar values of °hue to purple flours from other sources, and the maximum chroma was found in lyophilized pulp and lightness in fiber. Average moisture levels around 7.2% and water activity levels of 0.303 (0.194 for whole flour) in fractions suggested favorable storability, while the interaction of the powders with water was similar to other root and tuber powdered derivatives. Yampee periderm had the highest swelling power, oil absorption capacity, water holding capacity, and absorption index and capacity. Mucilage had a higher solubility index and outstanding emulsion activity, greater than 90%. Twelve anthocyanins, with new reports of petunidin derivatives for the species, and more than 30 phytochemicals were identified through advanced liquid chromatography techniques. The greatest amounts of pinitol and myo-inositol were found in the mucilage, and sucrose, glucose, and fructose prevailed in the other powders. Successfully characterized yampee fractions showed high potential as functional food ingredients.

From plant to nanomaterial: Green extraction of nanomucilage from Cordia dichotoma fruit and its multi-faceted biological and photocatalytic attributes

This study aimed to evaluate the extraction efficiency of mucilage from Cordia dichotoma fruits using various aqueous extraction methods, including microwave-assisted water extraction (MWE), hot-water extraction (HWE), and cold-water extraction (CWE). Different analytical techniques were employed to characterize the Cordia dichotoma mucilage (CDM). Additionally, the functional properties, anti-microbial, anti-inflammatory, and dye reduction potential of CDM were assessed. The results indicated a significantly (p < 0.05) higher yield of CDM (13.44 ± 0.94 %) using MWE compared to HWE (12.08 ± 0.82 %) and CWE (7.59 ± 0.73 %). The optimal extraction condition was utilized for the spray-drying process, yielding a spray-dried mucilage powder (SDMP) with a yield of 9.52 ± 1.27 %. The presence of galactose and arabinose as major sugar and functional groups such as OH, COOH, CH, and NH from proteins, uronic acids, and sugars were identified. CDM particles exhibited an irregular morphology and demonstrated thermal stability, with maximum weight loss occurring between 221.83 and 478.66 °C. The particle size of CDM was 681.16 ± 2.18 nm with a zeta potential of -21.46 ± 1.72 mV. Rheological analysis revealed that CDM exhibited shear-thinning behavior. Furthermore, CDM displayed inherent biological activities, including antimicrobial and anti-inflammatory properties. The dye reduction potential of CDM was evidenced by an 88.67 % degradation of indigo carmine dye. In summary, this study provides insights into the cost-effective extraction methods for CDM and its potential utilization as an eco-friendly material for dye reduction.

Structural and functional properties of polysaccharides extracted from three Dioscorea species

Dioscorea has a history spanning over 2000 years for both medicinal and edible purposes in China. It contains rich polysaccharides, which are frequently utilized as thickening and stabilizing agents in the food industry. However, there has been relatively little focus on polysaccharides from common Dioscorea species besides D. opposita, such as D. alata and D. esculenta. In this study, non-starch crude polysaccharides were isolated from D. opposita (BD), D. alata (WC), and D. esculenta (GZ). Their structures, physicochemical compositions, and functional properties were characterized and compared. The results indicated three polysaccharides all exhibited characteristic peaks of polysaccharides and possessed triple-helix structures. The Glc (36.78-83.90 %), Man (6.71-26.68 %), and GalA (8.54-10.22 %) were identified as the primary monosaccharide components. In terms of functionality, three polysaccharide solutions demonstrated non-Newtonian flow characteristics and displayed commendable thermal stability. It is worth noting that the antioxidant and emulsifying properties of polysaccharides isolated from D. opposita (BD) and D. alata (WC) were superior to those of D. esculenta (GZ), making them more suitable for use as antioxidants and stabilizers. By comparing polysaccharides derived from different Dioscorea species, this study provides valuable insights into the food, cosmetic, and pharmaceutical industries based on the unique properties of these different polysaccharides.

Structural and flow rheological properties of pumpkin pectic polysaccharide extracted by citric acid

The present study aimed to investigate the structural and physicochemical characteristics of acid-extracted pumpkin pectic polysaccharide (AcPP) and to evaluate their flow rheological properties. AcPP was extracted from pumpkin pulp using the citric acid extraction method. The physicochemical and structural properties were analyzed by chemical methods and instrumental analyses. The obtained results showed that AcPP consisted predominantly of GalA (85.99 %) and small amounts of Rha, Gal, and Ara, with the ratio of HG/RG-I being 81.39/16.75. In addition, AcPP had medium DE (45.34 %) and contained four macromolecular populations with different Mw of 106.03 (main), 10.15, 4.99, and 2.90 kDa. The NMR analysis further confirmed that AcPP contained a linear backbone consisting of α-1,4-linked GalA residues, some of which were partially methyl-esterified. Furthermore, AcPP was amorphous in nature and had favorable thermal stability. The effects of extrinsic factors on the flow rheological properties of AcPP were evaluated. In particular, the high concentrations of CaCl2 (8 mM) and MgCl2 (10 mM) were effective in enhancing the viscosity and non-Newtonian shear-thinning behavior of the AcPP solution. This study elucidates the unique molecular structure of AcPP and suggests the potential of AcPP as a rheology modifier in low-viscous and mineral-reinforced beverages.

Effects of Yam (Dioscorea rotundata) Mucilage on the Physical, Rheological and Stability Characteristics of Ice Cream

In the present investigation, yam mucilage was evaluated as a stabilizer and emulsifier in the formulation of vanilla flavored ice cream; physicochemical, rheological, and stability characteristics were determined. A completely randomized bifactorial design was used (yam mucilage: Carboxymethylcellulose ratio with the following levels: 100:0, 80:20, 50:50, and 20:80, and stabilizers concentration with levels of 0.4 and 0.8%). Results showed an increase in the protein content present in ice cream mixture as the amount of mucilage increases. Rheologically, it was found that ice cream has the characteristic behavior of a pseudoplastic fluid, presenting a viscoelastic structure where elastic behavior predominates. In addition, ratios with a higher content of mucilage incorporated a greater volume of air and presented the longest melting times, delaying drops falling time; in the same way mucilage gives ice cream a freezing temperature between −6.1 to −2.8 °C, indicating that the application of mucilage in food industry is possible due to its nutritional value, and it gives ice cream stability properties.

Dioscorea spp.: Comprehensive Review of Antioxidant Properties and Their Relation to Phytochemicals and Health Benefits

Dioscorea, consisting of over 600 species, is the most important genus in the Dioscoreaceae family; however, the practically used plants, which are commonly called yam, are restricted to a remarkably smaller number of species. Numerous studies have reported the high nutritional value of yam, particularly as an alternative source of starch and some important micronutrients. Several Dioscorea species are widely used for various medicinal purposes as well. In many studies, the bioactivities and health benefits of Dioscorea extracts and other preparations have been related to the presence of phytochemicals, which possess antioxidant properties; they are related mainly to radical-scavenging capacity in chemical assays and positive effects on the endogenous antioxidant system in cell-based and in vivo assays. Considering the increasing number of publications on this topic and the absence of comprehensive and focused review papers on antioxidant potential, this article summarizes the results of studies on the antioxidant properties of Dioscorea spp. and their relation to phytochemicals and health benefits. A comprehensive survey of the published articles has revealed that the majority of studies have been performed with plant tubers (rhizomes, roots), while reports on leaves are rather scarce. In general, leaf extracts demonstrated stronger antioxidant potential than tuber preparations. This may be related to the differences in phytochemical composition: saponins, phenanthrenes and, for some pigment-rich species (purple yams), anthocyanins are important constituents in tubers, while phenolic acids and flavonoids are characteristic phytochemicals in the leaves. The review may assist in explaining ethnopharmacological knowledge on the health benefits of Dioscorea plants and their preparations; moreover, it may foster further studies of poorly investigated species, as well as their wider application in developing new functional foods and nutraceuticals.

A Concise Review on Taro Mucilage: Extraction Techniques, Chemical Composition, Characterization, Applications, and Health Attributes

Taro (Colocasia esculenta) is an important source of carbohydrates as an energy source and is used as a staple food throughout the world. It is rich in mucilage and starch granules, making it a highly digestible ingredient. Mucilage can act as a matrix and a thickening, binding, emulsifying, or foaming agent in food, pharmaceutical, and several other fields of research. Moreover, mucilage can be extracted from several living organisms and has excellent functional properties, such as water-holding, oil-holding, and swelling capacities. Therefore, these remarkable functional properties make mucilage a promising ingredient with possible industrial applications. Furthermore, several extraction techniques, including enzyme-assisted, ultrasonication, microwave-assisted, aquatic, and solvent extraction methods, are used to obtain quantitative amounts of taro mucilage. Coldwater extraction with ethanol precipitation can be considered an effective and cost-effective technique to obtain high-quality mucilage with suitable industrial applications, whereas the ultrasonication method is more expensive but results in a higher amount of mucilage than other emerging techniques. Mucilage can also be used as a fat replacer or reducer, dye remover, coating agent, and antioxidating agent. Therefore, in this review, we detail the key properties related to the extraction techniques, chemical composition, and characterization of taro mucilage, along with its suitable applications and health benefits.

Characterization of the physicochemical properties, antioxidant activity, and antiproliferative activity of natural melanin from S. reiliana

This study aimed to characterize the physicochemical properties and stability of L-25 melanin extracted from Sporisorium reilianum (S. reiliana). The results showed that the maximum absorption wavelength of melanin was 215 nm. Reducing agents, heat, light, microwaving, oxidants, and common food additives did not affect the melanin. Additionally, it has a good metal stability except Mn²⁺. The IR spectra revealed the presence of O–H, N–H, C=O, and C=C bonds as well as carboxyl, alcohol hydroxyl, and phenolic hydroxyl groups and a pyran ring. L-25 melanin could be defined as DL-hydroxy phenylalanine (DOPA)-melanin. The antioxidant and antiproliferative were also measured. The melanin has a specific stability and high antioxidant activity, including a strong DPPH free radical scavenging ability, and protected damaged HepG2 cells by reducing reactive oxygen species, malondialdehyde, and lactate dehydrogenase content. In conclusion, S. reilianum represents a novel source of melanin, that could be applied to health food or food additives. Our results show that melanin from S. reilianum is a natural pigment with good stability that has a great prospect of development and application, providing a theoretical basis and methods for its further processing and development as a functional food.