Agave fructans: a review of their technological functionality and extraction processes.

Fructans are a polydisperse mixture of fructose polymers generally bound to a glucose molecule, in recent years, interest in their use has grown, either as a potential ingredient in functional foods or for their technological properties. The diversity of its applications lies in its structure and origin. Until now, the scientific approach has been more focused on inulin-type fructans and not so much on the effect of those of mixed branched structure as agave fructans. These have a complex structure with the presence of ß (2 - 1) and ß (2 - 6) bonds that give it prebiotic properties. In this context, a review is made of the general processes of extraction of agave fructans, as well as their technological functionality in the obtaining of base structures for the development of food products.

Comparative study of four extraction methods of fructans (agavins) from Agave durangensis: Heat treatment, ultrasound, microwave and simultaneous ultrasound-microwave.

Agavins (fructans from the agave plant) are used for their technological and prebiotic properties in developing functional foods. In this study, four extraction methods were evaluated: ultrasound (U), microwave (M), simultaneous ultrasound-microwave (UM), and heat treatment (HT). Isomers with a degree of polymerization (DP) > 10, as well as a significant concentration of fructooligosaccharides (FOS) were identified. The yield obtained by UM (72%) was similar to the other methods; however, the extraction time was shorter (5 min). In U, M, and HT the yields were 86, 76, and 85% in 35, 30, and 180 min, respectively. In addition, FTIR spectra showed evidence of regions corresponding to fatty acids and carbohydrates. Therefore, using UM to obtain agavins is a more ecological and faster process.

Natural pigments of plant origin: Classification, extraction and application in foods.

Color is the first attribute that influences the acceptance of foods as they become more attractive to consumers when they are more intense and uniform. In recent years, the interest of producers and consumers in purchasing products containing natural ingredients have constantly increased. Natural pigments are commonly extracted from fruits and vegetables, and have been proven to provide health benefits to reduce the risk of diseases such as type-1 diabetes, obesity, and coronary diseases. Additionally, advanced extraction and encapsulation technologies that make food matrices more efficient are useful tools for improving the use of these pigments. In this review, the state-of-the-art of pigments such as carotenoids, anthocyanins, and betalains of plant origin are discussed, including their main sources of production and the factors that affect their physicochemical stability. In addition, different extraction methods are discussed, listing their advantages and disadvantages, and providing some applications of natural pigments in food.

Effect of ultrasound and steam treatments on bioaccessibility of ß-carotene and physicochemical parameters in orange-fleshed sweet potato juice.

Several health benefits have been associated to orange-fleshed sweet potato owing to the existence of various bioactive compounds, including ß-carotene. The purpose of this study was to establish the effect of ultrasound and steam treatment on the bioaccessibility of ß-carotene, total polyphenols, antioxidant activity, polyphenol oxidase, peroxidase activity, and color in the orange-fleshed sweet potato juice. Sweet potato juice was processed using ultrasound (0.66 W cm-2 and 8 min), steam (2 min), and a combination of steam and ultrasound. The bioaccessibility of ß-carotene was increased in processed sweet potato juice, with samples treated by ultrasound showing the highest bioaccessibility (76.6%). Processing had no effect on antioxidant or enzyme activity, but resulted in significant changes in the color of the juice. As a processing technology, ultrasound enables preservation or improvement of the quality of sweet potato juice, and when conbined with other treatments, facilitates the development of new products.

Synbiotics: a technological approach in food applications.

The purpose of the present review is to explore the research about synbiotic food diversity, as well as the probiotics and prebiotics concentration used there in, and the different tests that this type of food is subjected to. The interaction probiotic-prebiotic-food is complex. The role of probiotics is clear, but the role of prebiotics is variable, as they are used for different purposes. The required doses in order to exert beneficial effects upon consumer health are adequate for probiotics, but not for prebiotics. The food processes affect in different ways the probiotics growth. It is essential to carry out more studies with protection technologies for probiotics, on the other hand, it is needed to assess if probiotics survival is because of the food matrix or because of the prebiotic with further experimentation.

Changes in the microstructural, textural, thermal and sensory properties of apple leathers containing added agavins and inulin.

In this study the effect of agavin and inulin addition on the microstructural, textural, thermal and sensory properties of apple leathers was investigated. Agavins and inulin were added to leathers at two concentration levels (6 and 4%) individually and as a mixture. Scanning Electron Microscopy (SEM) revealed more compact and less porous matrices in the 6% concentration with respect to the control, influencing leather texture. In formulations with agavins the texture was significantly (p < 0.05) smoother than in those with inulin. No relationship was found between hardness and glass transition temperature (Tg), but there was a significant difference between treated leathers and the control. The acceptability of the product showed a direct relationship with the hardness. There were significant changes in the leathers after storage. Agavins and inulin exhibited different technological properties and considering the texturising effect of the agavins, their potential for use in the food industry is promising.

Husk Tomato (Physalis ixocarpa Brot.) Waste as a Promising Source of Pectin: Extraction and Physicochemical Characterization.

Husk tomato (Physalis ixocarpa Brot. var. Rendidora) waste was evaluated as a source of specialized pectin, and pectin extracted from this waste was characterized physicochemically. Fruit was blanched for 10 or 15 min and extracted in 0.1 N HCl for 15 to 25 min. Extracted pectin was subjected to physicochemical analysis. For all extraction conditions, the percentage of anhydrogalacturonic acid exceeded 60%, indicating that husk tomato was a good source of pectin. The degree of esterification of pectin molecules was 63% to 91%. The amount of extracted pectin decreased with increasing extraction time. The apparent viscosity of husk tomato pectin showed the characteristic behavior of pseudoplastic fluids. Neutral sugars were identified, and the amounts of 6 sugars (fucose, rhamnose, arabinose, galactose, glucose, and xylose) were quantified. Sugars identified in husk tomato pectin and present in the Rhamnogalacturonan I region, arabinose, galactose, and rhamnose suggest a highly branched structure, which will influence its future applications. Molecular weight values were 542 to 699 kDa, exceeding molecular weight values reported for commercial citrus pectins from 134 to 480 kDa. The extraction process significantly (P < 0.05) influenced the physicochemical properties of pectin. Up to 19.8% from the total amount of pectin in the husk tomato was extracted by 10 min of blanching and 20 min of a more heat treatment. Our findings indicate that husk tomato can be a good alternative source of pectin having highly distinctive physicochemical characteristics.

Effect of high-pressure homogenization on the physical and antioxidant properties of Quercus resinosa infusions encapsulated by spray-drying.

Quercus resinosa leaves are used in northern Mexico as a refreshing beverage rich in polyphenolic compounds. These leaves show astringency and hence need taste masking for incorporating in a food product. They also interact with many other food components and are not very stable to food processing environments, thus it is important to protect them and a common way is by encapsulation. In the present study the use of encapsulation by spray-drying of Quercus resinosa leaves infusions was evaluated. Q. resinosa leaves were collected, air dried, and milled prior to infusion preparation. Lactose-sodium caseinate blends at 3 different proportions (11 : 4%, 9 : 6%, and 7 : 8%) were dispersed with a constant amount of lyophilized infusion (0.075%) and processed under high-pressure homogenization (0, 100, 200, 300 MPa). Total phenolic content, DPPH kinetic analysis, deoxy-D-ribose oxidation inhibition, rheological evaluation, and particle size analysis were performed to evaluate the obtained capsules. High antioxidant activity was shown by capsules despite their very low concentration when inhibiting deoxy-D-ribose oxidation. Chain breaking rate was related to polyphenolic concentration in capsules. Using lactose-caseinate blends produces capsules of submicron to nanometer size that retain the good antioxidant capacities of original infusions.