Effects of heating temperature on the total phenolic compound, antioxidative ability and the stability of dioscorin of various yam cultivars

Assessment of nutritional properties and phenolic characterization of freshly harvested Dendrocalamus hamiltoni shoots and processed bamboo candy

The free and bound phenolic constituents in Dendrocalamus hamiltonii shoots were evaluated and compared to processed bamboo candy. Preliminary proximate analysis revealed a percent reduction in moisture and protein with a less significant change in fibre content. The fresh free phenolic extract (FFPE) exhibited a total phenolics of 131.22 mg GAE/g and recovered 48.29 mg GAE/g phenolic content in bound fraction (FBPE). Results demonstrated higher loss of free phenolics after processing compared to bound fraction (CBPE). Although similar results were observed in total flavonoid content. Antioxidant activity was reduced after candy processing, with fresh shoots having the lowest percent inhibition (IC₅₀) against DPPH^· and ABTS^· radicals. Although both free and bound fractions of candy demonstrated effective antioxidant activity. HPLC analysis revealed that FFPE contained more chlorogenic acid (0.14 mg/10 g) and cinnamic acid (0.75 mg/10 g) than CFPE. Quercetin was undetected in all free fractions but was found in bound form.

Effect of Different Extraction Methods and Geographical Origins on the Total Phenolic Yield, Composition, and Antimicrobial Activity of Sugarcane Bagasse Extracts

Several parameters, including particle size, solvent, temperature, and extraction method, affect phenolic compounds' extraction yield from a plant matrix. Considering the wide availability of sugarcane bagasse (SCB), this study analyzed the effect of different extraction methods and geographical origins on the yield, quality, and antimicrobial activity of phenolic compounds from SCB extracts. Samples from three geographical locations (Veracruz, Mexico; Santa Rosa, Texas, USA; and St. Mary, Louisiana, USA) were analyzed. Extraction was performed using an orbital shaker or ultrasonic bath at various times at a fixed temperature of 50°C, with 90% ethanol or methanol. The highest yield (5.91 mg GAE) was obtained using an orbital shaker for 24 h with 90% methanol as the solvent. HPLC-MS identified desferrioxamine b, baicalein, madecassic acid, and podototarin at different concentrations in all three SCB samples. The antimicrobial activity of these compounds was tested against Escherichia coli K12, Bacillus cereus, Enterobacter aerogenes, Streptococcus aureus, and Enterobacter cloacae. The antimicrobial activity was also tested against modifications of the Saccharomyces cerevisiae: the MutL Homolog 1 (MLH1), Slow Growth Suppressor (SGS1), O-6-MethylGuanine-DNA methyltransferase (MGT1), and RADiation sensitive (RAD14), carrying mutations related to different cancer types. In addition, the results were compared with the effect of ampicillin and kanamycin. The SCB extracts showed up to 90% growth inhibition against B. cereus at 200–800 μg/mL and 50% growth inhibition against S. aureus at 800 μg/mL. The inhibitory effect against modified yeast SGS1, RAD14, and MLH1 was 50–80% at 800 μg/mL. The percentage of inhibition and the phenolic compound contents differed depending on the origin of the SCB sample. These findings are promising for using this industrial byproduct to obtain compounds for nutraceutical, food additive, or medical uses.

Use of the abrasion technique in minimal processing as an alternative to increase purchase acceptability and minimize browning in yam

BACKGROUND

The present study investigated the sensory acceptance, oxidative damage and protection, and possible anatomical-structural damage of cells from the surface of shapes of minimally processed yam. The tubers were minimally processed into the peeled rondelle, dice and 'chateau cut' (chateau) shapes, the latter of which was obtained after performing the abrasion technique. Control treatment corresponded to the rondelle shape with the periderm. The pieces were kept packed at 5 ± 2 °C for 14 days.

RESULTS

Peeled rondelle and chateau were sensorially the most well-accepted yam shapes and achieved the highest purchase intention. The enzymes were partially modulated by the detected H₂ O₂ levels. Oxidative burst lasted longer in the minimally processed tissues than in the control. Polyphenol oxidase activity showed a clear difference in behavior between the minimally processed pieces and the control. Minimal processing induced transient increases in phenolic compounds, for which the expression was lowest in the abraded pieces. On the other hand, these pieces exhibited greater cell collapse on the surface of the amyliferous parenchyma.

CONCLUSION

Based on the results of the trained panel, the abrasion technique is an alternative to provide shapes that are better accepted and marketable, more resistant to browning, and can be stored for up to 12 days. Resistance to browning may be related to a more efficient modulation of enzymatic antioxidant systems and intense deposition of cell debris on the surface of the amyliferous parenchyma. © 2021 Society of Chemical Industry.

Physicochemical, enzymatic and molecular characterisation of the storage protein of aerial tuber, Dioscorea bulbifera Linn

BACKGROUND

The storage protein of the aerial tuber of Dioscorea bulbifera was purified and its physicochemical, enzymatic and molecular properties determined with a view to comparing its functionality and genetic relatedness with other storage proteins.

RESULTS

The purified protein had molecular weight of 21 kDa. The protein showed carbonic anhydrase, trypsin inhibitory, dehydroascorbate reductase and monodehydroascorbate reductase activities. Amplifications with polymerase chain reactions resulted in the detection of two genes encoding the storage protein. The deduced amino acid sequence of the shorter and larger genes had homologies with the storage proteins of members of the Dioscorea family.

CONCLUSION

The study concluded that the storage protein of the aerial tuber of D. bulbifera had similar properties with those of other Dioscorea species and may be suitable for development as functional food.

Degradation kinetics of anthocyanin and physicochemical changes in fermented turnip juice exposed to pulsed UV light

In this study, the effects of pulsed UV (PUV) light on the degradation kinetics of anthocyanins and physicochemical properties of turnip juice were investigated. PUV light was applied to turnip juice at 3 different distances (5, 8, 13 cm) from the quartz window of the xenon lamp for 5 different times (5, 15, 30, 45, 60 s). The pH, total acidity (% lactic acid), monomeric anthocyanin content, color density, hue, brightness, and percent color components (yellow, red, and blue) of turnip juice changed significantly after PUV-light treatments at each level. The maximum degradation of anthocyanin after PUV-light treatments was found to be about 63%. The anthocyanin degradation, brightness, yellow and blue color (%) increased, while red color (%) decreased with longer treatment time and shorter distance. The degradation of monomeric anthocyanins in turnip juice exposed to PUV light was described by the Weibull model (R² 0.982-0.998, RMSE 0.087-0.133) more accurately than the first-order kinetics (R² 0.906-0.992, RMSE 0.071-0.192).

Estrogenic Effects of the Extracts from the Chinese Yam (Dioscorea opposite Thunb.) and Its Effective Compounds in Vitro and in Vivo

BACKGROUND

The aim of this study was to explore the estrogenic effects of the extracts from Chinese yam and its effective compounds.

METHODS

The activity of the yam was investigated by the uterine weight gain of mice and a proliferation assay of breast cancer cell lines (MCF-7 cell); the estrogenic activity was comprehensively evaluated by a serum pharmacology experiment. The levels of estradiol (E2), follicle stimulating hormone (FSH), and luteinizing hormone (LH) were also measured. Western blot analysis and antagonist assays with faslodex (ICI182,780), methylpiperidino-pyrazole (MPP), Delta (9) -tetrahydrocannabinol (THC), and G-15 were used to explore the mechanism of the effects of the yam. To find the effective compounds of the yam which play a role in its estrogen-like effects, we used the same methods to study the effects of adenosine and arbutin.

RESULTS

The Chinese yam and two main compounds, adenosine and arbutin, have estrogen-like effects. The mechanism of the yam which plays a role in its estrogen-like effects was mainly mediated by the estrogen receptors ERα, ERβ, and GPR30; that of adenosine was mainly mediated by estrogen receptors ERα and ERβ, and that of arbutin was mainly mediated by estrogen receptors ERβ and GPR30.

CONCLUSIONS

The Chinese yam has estrogen-like effects; adenosine and arbutin are two of the effective compounds in the yam which play a role in its estrogen-like effects.

Antioxidant and Antitumor Activities of the Extracts from Chinese Yam (Dioscorea opposite Thunb.) Flesh and Peel and the Effective Compounds

The aims of this study are to investigate the antioxidant and antitumor activities of the water and ethanol extracts isolated from Chinese yam (Dioscorea opposite Thunb.) flesh (CYF) and peel (CYP) and the effective compounds. It was found that all peel portions have a better effect on reactive oxygen (ROS) scavenging assay than meat portions, especially for the water extract of Chinese yam peel (CYP-W). Its IC50 values for hydroxyl radical (OH•) scavenging assay (744.25 ± 3.46 μg/mL) and for 1,1-diphenyl-2-picrylhydrazyl scavenging assay (374.85 ± 6.78 μg/mL) were both lower than that of yam flesh (CYF-W). Furthermore, the antitumor property of yam peel was more effective than that of yam flesh (CYF-W) on mouse models, with tumor inhibition rates were 47.92% and 27.41% for Ehrlich Ascites Tumor (EAC) model and 40.44% and 24.22% for H22 hepatocarcinoma tumor (H22) model. Meanwhile, extracts of peel showed higher allantoin, total flavonoids, and total phenolics contents than extracts of flesh. In conclusion, this study demonstrated that CYP-W exerted better antitumor activity than flesh extracts and the scavenging ROS effects were also significantly higher in the CYP-W in vitro. Moreover, the data indicated that allantoin may play an important role on antioxidative and antitumor capacity in yam peel.

Roots and Tuber Crops as Functional Foods: A Review on Phytochemical Constituents and Their Potential Health Benefits

Starchy roots and tuber crops play a pivotal role in the human diet. There are number of roots and tubers which make an extensive biodiversity even within the same geographical location. Thus, they add variety to the diet in addition to offering numerous desirable nutritional and health benefits such as antioxidative, hypoglycemic, hypocholesterolemic, antimicrobial, and immunomodulatory activities. A number of bioactive constituents such as phenolic compounds, saponins, bioactive proteins, glycoalkaloids, and phytic acids are responsible for the observed effects. Many starchy tuber crops, except the common potatoes, sweet potatoes, and cassava, are not yet fully explored for their nutritional and health benefits. In Asian countries, some edible tubers are also used as traditional medicinal. A variety of foods can be prepared using tubers and they may also be used in industrial applications. Processing may affect the bioactivities of constituent compounds. Tubers have an immense potential as functional foods and nutraceutical ingredients to be explored in disease risk reduction and wellness.

Effect of Vacuum Frying on Changes in Quality Attributes of Jackfruit (Artocarpus heterophyllus) Bulb Slices

The effect of frying temperatures and durations on the quality of vacuum fried jackfruit (JF) chips was evaluated. Moisture content and breaking force of JF chips decreased with increase in frying temperature and time during vacuum frying whereas the oil content increased. The frying time for JF chips was found to be 30, 25, and 20 minutes at 80, 90, and 100°C, respectively. JF chips fried at higher temperature resulted in maximum shrinkage (48%). The lightness in terms of hunter L^* value decreased significantly (P < 0.05) during frying. Sensory evaluation showed maximum acceptability for JF chips fried at 90°C for 25 min. Frying under vacuum at lower temperatures was found to retain bioactive compounds such as total phenolics, total flavonoids, and total carotenoids in JF chips. Almost 90% of carotenoids were lost from the samples after 30 min of frying at 100°C.

Phenolic biotransformations during conversion of ferulic acid to vanillin by lactic acid bacteria

Vanillin is widely used as food additive and as a masking agent in various pharmaceutical formulations. Ferulic acid is an important precursor of vanillin that is available in abundance in cell walls of cereals like wheat, corn, and rice. Phenolic biotransformations can occur during growth of lactic acid bacteria (LAB), and their production can be made feasible using specialized LAB strains that have been reported to produce ferulic acid esterases. The present study aimed at screening a panel of LAB isolates for their ability to release phenolics from agrowaste materials like rice bran and their biotransformation to industrially important compounds such as ferulic acid, 4-ethyl phenol, vanillic acid, vanillin, and vanillyl alcohol. Bacterial isolates were evaluated using ferulic acid esterase, ferulic acid decarboxylase, and vanillin dehydrogenase assays. This work highlights the importance of lactic acid bacteria in phenolic biotransformations for the development of food grade flavours and additives.

Inhibition of α-amylase and α-glucosidase activities by ethanolic extract of Telfairia occidentalis (fluted pumpkin) leaf

OBJECTIVE

To investigate the inhibitory effect of Telfairia occidentalis Hook f. (Curcubitaceae) (T. occidentalis) leaf on key enzyme linked to type-2 diabetes (α - amylase and α - glucosidase) as well as assess the effect of blanching (a commonly practiced food processing technique) of the vegetable on these key enzymes.

METHODS

Fresh leaves of T. occidentalis were blanched in hot water for 10 minutes, and the extracts of both the fresh and blanched vegetables were prepared and used for subsequent analysis. The inhibitory effect of the extract on α - amylase and α - glucosidase activities as well as some antioxidant parameter was determined in vitro.

RESULTS

The result revealed that unprocessed T. occidentalis leaf reduce Fe(3+) to Fe(2+) and also inhibited α - amylase and α - glucosidase activities in a dose dependent manner. However, blanching of the leafy vegetables caused a significant (P<0.05) increase in the antioxidant properties but decrease their ability to inhibit α - amylase and α - glucosidase activities.

CONCLUSIONS

This antioxidant properties and enzyme inhibition could be part of the mechanism by which they are used in the treatment/prevention of type-2 diabetes. However, the blanched vegetable reduces their ability to inhibit both α - amylase and α - glucosidase activity in vitro.

Inhibitory effect of some tropical green leafy vegetables on key enzymes linked to Alzheimer's disease and some pro-oxidant induced lipid peroxidation in rats' brain

This study sought to investigate the inhibitory effect of some commonly consumed Nigerian green leafy vegetables (raw and blanched) on acetylcholinesterase and butyrylcholinesterase (key enzyme linked to Alzheimer's disease) activities and some pro-oxidants (FeSO4, Sodium nitroprusside and Quinolinic acid) induced lipid peroxidation in rat brain in vitro. Three commonly consumed green leafy vegetables in Nigeria [Amarantus cruentus (Arowojeja), Struchium sparganophora (Ewuro-odo) and Telfairia occidentalis (Ugwu] were blanched in hot water for 10 min, and the extracts of the raw and blanched vegetables were prepared and used for subsequent analysis. The result revealed that all the vegetables inhibited acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activity as well as the pro-oxidants induced lipid peroxidation in rat brain in a dose dependent manner; however, Amarantus cruentus extract (EC50 = 97.9 μg/ml) had the highest inhibitory effect on acetylcholinesterase activity while Telfairia occidentalis extract (EC50 = 52.7 μg/ml) had the highest inhibitory effect on butyrylcholinesterase activity. However, blanching of the vegetables caused a significant (P < 0.05) decrease in the inhibitory effect of the vegetables on AChE activities while it enhanced the inhibition of the pro-oxidants induced lipid peroxidation in rat brain in vitro. Therefore, some of the possible mechanism by which green leafy vegetables exert their neuroprotective activities could be through the inhibition of acetylcholinesterase and butyrylcholinesterase activities and prevention of lipid peroxidation in the brain. However, blanching of the vegetables could reduce their ability to inhibit acetylcholinesterase and butyrylcholinesterase activity.

Ohmic and Conventional Heating of Pomegranate Juice: Effects on Rheology, Color, and Total Phenolics

Ohmic heating is an alternative fast-heating method especially for liquid foods. In this study, pomegranate juice samples, prepared by two different extraction methods, were heated ohmically by matching the same thermal history, with that of the conventional method. The ohmic heating application was conducted by changing the voltage gradient (10—40 V/cm) at 50 Hz. The samples were heated from 20 ° C to 90°C and held at 90 °C for different treatment times (0, 3, 6, 9 or 12 min). Although rheological properties, color, and total phenolic content (TPC) values changed at the initial heating up period, there were no significant changes during holding period (p < 0.05). Non-Newtonian (power law) rheology model had higher regression coefficient than Newtonian model, and the extraction method affected the consistency of pomegranate juice samples (p < 0.05). Color values of juice extracted from arils (APJ) was better than that of juice extracted from whole fruits (PPJ), as PPJ contained higher amount of TPC (p < 0.05). Since the heating method did not affect the rheological properties, color, and TPC values, it could be said that there was no electrical effect rather than thermal effects during ohmic heating of pomegranate juice. Ohmic heating could be recommended as an alternative fast-heating method for fruit juices.

Yam storage protein dioscorins from Dioscorea alata and Dioscorea japonica exhibit distinct immunomodulatory activities in mice

The aim of this study was to elucidate the effect of the major storage protein dioscorin isolated from two different yam species, Tainong No. 1 (TN1-dioscorins) and Japanese yam (Dj-dioscorins), on the immune activities of mice. Dj-dioscorins, like TN1-dioscorins, could induce expression of the pro-inflammatory cytokines and stimulate phagocytosis of RAW 264.7. Intraperitoneal injection of the TN1-dioscorins into mice stimulated phagocytosis of bone marrow, spleen, and thymic cells. In contrast, the T and B cells in bone marrow, spleen, and thymus isolated from mice injected with Dj-dioscorins had higher proliferative responses to mitogens. Furthermore, Dj-dioscorins enhanced proliferation of CD4(+), CD8(+), and Tim3(+) (Th1) cells in spleen and CD19(+) cells in both spleen and thymus. Supplement of Dj-dioscorins in the lymphoid cells isolated from Dj-dioscorins primed mice induced cell proliferation of both spleen and thymic cells. These findings indicated that TN1-dioscorins have a higher ability to stimulate the phagocytic activity of the lymphoid cells than Dj-dioscorins, whereas Dj-dioscorins possess more abilities than TN1-dioscorins to enhance the proliferation of the lymphoid cells.