Stability of fructooligosaccharides, sugars and colour of yacon (Smallanthus sonchifolius ) roots during blanching and drying

Machine and Deep Learning in the Evaluation of Selected Qualitative Characteristics of Sweet Potatoes Obtained under Different Convective Drying Conditions

This paper discusses the use of various methods to distinguish between slices of sweet potato dried in different conditions. The drying conditions varied in terms of temperature, the values were: 60 °C, 70 °C, 80 °C, and 90 °C. Examination methods included instrumental texture analysis using a texturometer and digital texture analysis based on macroscopic images. Classification of acquired data involved the use of machine learning techniques using various types of artificial neural networks, such as convolutional neural networks (CNNs) and multi-layer perceptron (MLP). As a result, in the convective drying, changes in color darkening were found in products with the following temperature values: 60 °C (L = 83.41), 70 °C (L = 81.11), 80 °C (L = 79.02), and 90 °C (L = 75.53). The best-generated model achieved an overall classification efficiency of 77%. Sweet potato dried at 90 °C proved to be completely distinguishable from other classes, among which classification efficiency varied between 61–83% depending on the class. This means that image analysis using deep convolutional artificial neural networks is a valuable tool in the context of assessing the quality of convective-dried sweet potato slices.

Effects of yacon flour associated with an energy restricted diet on intestinal permeability, fecal short chain fatty acids, oxidative stress and inflammation markers levels in adults with obesity or overweight: a randomized, double blind, placebo controlled clinical trial

Objective

Yacon flour is rich in bioactive compounds (phenolic compounds and fructooligosaccharides (FOS)), and may therefore reduce the risk of diseases associated with excess body weight. However, its effect on fecal short chain fatty acids (SCFA), intestinal permeability, oxidative stress and inflammation markers has not been studied in adult humans with excess body weight. Thus, we evaluated the effect of the consumption of yacon flour on these variables.

Methods

Twenty-six excess body weight (30.4 ± 2.4 kg/m²) adults (31.3 ± 8.5y) were randomized to one of two groups (yacon flour or control; n = 13) on a double blind clinical trial. Subjects received a breakfast drink containing or not yacon flour (25g) associated with an energy restricted diet, for six weeks. The flour chemical characterization, FOS and total phenolics contents were evaluated. Antioxidant capacity was evaluated in vitro and in vivo (plasma). Intestinal permeability, fecal SCFA, oxidative stress and inflammatory markers also were evaluated in vivo.

Results

Yacon flour was well tolerated. It presented an in vitro and in vivo antioxidant capacity, increased plasma total antioxidant capacity (Δ_YAC: 49.16 (-4.20; 156.63)) and reduced protein carbonyl concentrations (Δ_YAC: -0.98 (-1.54; -0.42)). A reduction in SCFAs was observed in both groups (Δ_acetic: -3.16 (-5.07; -0.95) vs. -1.05 (-2.65; 1.11); Δ_propionic: -1.05 (-2.60;-0.38) vs. -0.41 (-2.08; 0.09); Δ_butyric -0.75 (-1.38; -0.04) vs. -0.28 (-0.98; 0.11), for YAC and CON, respectively). Other variables did not change.

Conclusion

The yacon flour increased the plasma antioxidant capacity, decreased oxidative stress and SCFAs in adults with obesity or overweight.

Application of ATR-FTIR spectroscopy for profiling of non-structural carbohydrates in onion (Allium cepa L.) bulbs

Qualitative and quantitative composition of non-structural carbohydrates comprising glucose, fructose, sucrose and fructooligosaccharides (FOS) is one of the key determinants of market suitability, storability and technological processability of onions. To develop a cost-effective and rapid tool for carbohydrate profiling, applicability of attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy of onion juice was investigated with special regard to FOS patterns. As reference, detailed carbohydrate profiles of onion juices were generated by high-performance liquid chromatography coupled with evaporative light scattering detection (HPLC-ELSD). Hierarchical cluster analysis (HCA) of ATR-FTIR spectra was successfully applied for classifying onions into fresh market, storage and dehydrator type according to HPLC-ELSD profiles. A bootstrapping method for automatized test-set validation by projection to latent structures (PLS) algorithms using HPLC and ATR-FTIR spectroscopy data was developed. Model statistics showed promising perspectives for reliable quantification of individual saccharides and sum parameters. The presented methodology allows estimating the nutritional and pre-biotic value directly during cultivation and processing.

High humidity air-impingement blanching (HHAIB) improves drying characteristics and quality of ground-cover chrysanthemum heads

Effects of high humidity air-impingement blanching (HHAIB) temperature, relative humidity over a range of application time and drying temperature on air-impingement drying kinetics, colour attributes, browning index, blanching weight loss and total flavonoids content of chrysanthemum heads were studied. HHAIB could shorten the drying time of chrysanthemum heads significantly (p < 0.05) by up to 52% compared to the control group without blanching. Meanwhile blanching humidity has a greater influence on drying kinetic than other blanching parameters. Deff values of samples declined first and rose later with the growth of blanching humidity, while increased continuously with the growth of blanching temperature. The highest growth of total flavonoids content can be up to 21.6% under the HHAIB blanching conditions (110 °C of blanching temperature, 45% of relative humidity, 150 s of blanching time) in comparison with the control group. Lightness of all blanched samples was lower than the control group, and redness and total colour difference under different blanching conditions showed significant differences compared to the control group, while no obvious variation was observed in terms of yellowness values.

Consumption of yacon flour improves body composition and intestinal function in overweight adults: A randomized, double-blind, placebo-controlled clinical trial

BACKGROUND & AIMS

Yacon root is a natural source of fructooligosaccharides (FOS), and it has been studied for its potential effect as a functional food. However, FOS in the in natura root are rapidly hydrolyzed. Thus, the use of dehydrated products such as flour ensures stability of FOS. The effect of chronic consumption of yacon flour on body composition, food intake and of biochemical variables concentration has not yet been evaluated in humans. Thus, we evaluated the effects of yacon flour consumption on these variables associated with excess body weight.

METHODS

Twenty-six adults (31.3 ± 8.5 years) with excess weight (30.4 ± 2.4 kg/m², 40.16 ± 6.7% body fat) participated in this randomized, double-blind, six-week study. Subjects were randomly allocated to one of the experimental groups (control (n = 13) or yacon flour (n = 13)), received the prescription of energy-restricted diets (- 500 kcal/day) and daily consumed a breakfast drink not containing or containing 25 g of yacon flour (0.1 g of FOS/kg body weight). At the beginning and at the end of the study, biochemical analyses (glycemia, insulinemia, lipid profile and liver function markers), anthropometrics (weight, waist, hip and neck circumference and sagittal abdominal diameter), body composition (lean mass, total body fat, trunk fat, android fat and gynoid fat), blood pressure, intestinal function, and food intake were assessed.

RESULTS

Daily yacon flour consumption was well tolerated, did not cause adverse gastrointestinal effects, increased dietary fiber consumption, promoted greater body weight, waist circumference, waist to height index, sagittal abdominal diameter, and body fat reduction, besides improving bowel function in comparison to the control group.

CONCLUSIONS

Yacon flour served as a natural fiber supplement and proved to be an effective adjuvant to be used in nutritional strategies to control excess body weight.

A Novel Color Parametric Technique for Kinetic Evaluation of Thermal Degradation and Stability of Fresh-Cut Yacon Slices

Fresh-cut yacon slices were first heat treated (60–80 °C, 5–25 min) and then exposed to air at room temperature for up to 10 min. Color parameters of internal surface were measured and two kinetic models were evaluated: 1) Color degradation during thermal treatment, and 2) Color stability during subsequent air exposure. More severe treatments led to lower color quality but higher stability. The relative white index was the best color parameter and the color changes followed a zero-order kinetics. The temperature dependence of rate constants were evaluated using the Arrhenius model. The activation energy for color degradation was 14.7 kJ/mol, and for color stability it was 47.9 kJ/mol indicating color stability parameters to be more sensitive to temperatures than color degradation. The color parameter models developed were comparable to polyphenoloxidase inactivation model and provided a rapid physical method for evaluating color degradation and subsequent color stability of yacon slices.