Rheological properties and microstructure of wheat flour dough systems with enzyme-hydrolyzed mashed potatoes.

The interest in incorporating potatoes into wheat dough is increasing. However, potatoes exhibit significant viscosity during thermal processing, affecting product processing and quality. This study aims to find an effective method to reduce the viscosity of mashed potatoes. We aimed to compare the effects of different enzymes (α-amylase, ß-amylase, and flavourzyme) and concentrations (0.01%, 0.05%, and 0.1%) on the micromorphology and rheological properties of mashed potatoes and potato-wheat dough. The impact of flavourzyme was the most significant (p<0.05). When enzyme concentration increased, viscosity decreased, and the degree of structural damage, indicated by increased porosity. Notably, the addition of flavourzyme can increase the content of sweet and umami free amino acids, improving the flavor of mashed potatoes. The scanning electron microscopy and confocal laser scanning microscopy images of potato-wheat dough revealed that enzyme-hydrolyzed mashed potatoes had improved homogeneity, reestablished the dough continuity, and strengthened the three-dimensional structure comprising proteins and starch. Notably, flavourzyme demonstrated the most significant effect on enhancing the protein-starch network structure. This was attributed to the exposure of functional groups resulting from protein hydrolysis, facilitating interaction with starch molecules. Our findings indicate that the addition of 0.1% flavourzyme (500 LAPU/g, pH 5.5, 55 ± 2°C, 30 min treated) was the most effective in reducing viscosity and reconstructing the gluten network. Enzymatic hydrolysis plays a vital role in the production of high-quality potato products, with particular importance in the baking industry, where flavourzyme exhibits significant potential. PRACTICAL APPLICATION: Enzymatic hydrolysis plays a vital role in the production of high-quality potato products, with particular importance in the baking industry, where flavourzyme exhibits significant potential.

Low glycemic index potato biscuits alleviate physio-histological damage and gut dysbiosis in rats with type-2 diabetes mellitus induced by high-sugar and high-fat diet and streptozotocin.

Type 2 diabetes mellitus (T2DM) is the most common type of diabetes globally and poses a major concern for human health. This study aimed to investigate the effects on T2DM of low-glycemic index (GI) potato biscuits with oat bran and inulin as functional additives. T2DM was induced in rats by streptozotocin (STZ) and a high-sugar and high-fat diet. The alleviation of T2DM by low-GI potato biscuits at different doses was evaluated based on the analysis of glycolipid levels, histological observations, inflammatory markers, and gut microbiota structure. Compared to wheat biscuits, low-GI potato biscuits resulted in lower postprandial blood glucose levels. After 8 weeks of intervention, fasting blood sugar levels were 16.9% lower in T2DM rats fed high-dose low-GI potato biscuits than in untreated T2DM rats. Moreover, the intervention with low-GI potato biscuits significantly alleviated T2DM-induced pathological damage, glucose and lipid metabolic disorders, and inflammation by reversing the levels of total cholesterol, triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, transforming growth factor-ß, interleukin-1ß, interleukin-6 and tumor necrosis factor-α. Moreover, the levels of short-chain fatty acids and gut microbiota structure in T2DM rats were significantly reversed. The abundance of beneficial bacteria (e.g., Bifidobacterium, Lachnoclostridium, Roseburia) in the gut of T2DM rats was significantly increased whereas the abundance of Escherichia-Shigella and Desulfovibrio decreased. The present study revealed that low-GI potato biscuits alleviated damages caused by high-sugar and high-fat diet- and STZ-induced T2DM in rats, as well as reversed disturbances in the gut microbiota. Thus, low-GI potato biscuits are potentially beneficial to T2DM patients.

Effect of high intensity ultrasonic treatment on structural, rheological, and gelling properties of potato protein isolate and its co-gelation properties with egg white protein.

The study aimed to investigate the effect of high intensity ultrasonic (HIU) treatment at different times (0, 10, 20, and 30 min) on the structure and gel properties of water-soluble potato protein isolate (WPPI) and to further investigate the improvement of gel properties of ultrasonicated WPPI (UWPPI) by the addition of egg white protein (EWP). HIU reduced the particle size of WPPI, whose structure became loose and disordered, which improved gelling properties of UWPPI. Fourier transform infrared results indicated that α-helix content decreased, whereas the proportion of irregular curl increased with the increase in ultrasonication time (0-20 min), indicating that the initially ordered structure of UWPPI became disordered. After HIU treatment, the free sulfhydryl groups of UWPPI and surface hydrophobicity decreased and fluorescence intensity increased. These results demonstrated that the HIU loosened the structure of UWPPI, exposing more chromogenic groups while embedding more hydrophilic groups. After thermal induction, UWPPI gel hardness increased and exhibited excellent water holding capacity. After the addition of EWP, rheological properties stabilized, and the hardness of UWPPI-EWP gels increased significantly, forming internally structured protein gels with a tightly ordered structure and increased brightness. Thus, HIU changed the structure and gelling properties of WPPI, and the addition of EWP further enhanced the performance of hybrid protein gels. PRACTICAL APPLICATION: High intensity ultrasonic changed the structure of water-soluble potato protein isolate (WPPI) and improved the properties of WPPI gels. The addition of egg white protein significantly improved the quality of mixed protein gels which showed great potential industrial value.

Relationship among gelatinization, retrogradation behavior, and impedance characteristics of potato starch.

In this study, the physicochemical properties of potato starch from different varieties were investigated. Furthermore, the relationships among gelatinization, retrogradation behavior, and impedance characteristics of potato starch gels were evaluated by texture analysis, low-field nuclear magnetic resonance spectroscopy, and electrical impedance spectroscopy. The results indicated amylose content was positively correlated with setback viscosity, and negatively correlated with To and ΔH. In addition, impedance values of potato starch gels differed in a frequency-dependent manner. Notably, higher frequencies resulted in low diffusion of ions in prepared gels, which combined with the concentration of mobile ions in free water, led to a gradual decrease in impedance module. Compared with phase values, impedance module showed high correlation with gelatinization parameters (To, Tp, and Tc) and viscosity parameters (peak temperature and setback viscosity), more notably at frequencies below 100 Hz. In this context, the electric current flowed through mobile ions that interacted with bound water attached to the starch molecules at lower voltage frequencies, and were repressed by the formation of an ordered and compact gel network during retrogradation. Collectively, these results indicate that impedance spectroscopy can be potentially used as an efficient and reliable method to predict gelatinization and retrogradation behavior of potato starch.

Thermal, structural, rheological and morphological properties of potato starch-gluten model dough systems: Effect of degree of starch pre-gelatinization.

The effect elicited by degree of starch gelatinization on the rheological properties of starch-gluten model dough was examined. Gelatinization temperature, water retention capacity, linear viscoelastic region, and maximum creep compliance of potato starch-gluten composites increased, while enthalpy and frequency dependence decreased with increasing degree of starch gelatinization. More membrane-like structures and larger holes were observed in potato starch-gluten model dough; the amount of gluten ß-sheet increased, while the amount of random coil and ß-turn decreased as degree of gelatinization increased. The starch gelling and starch-gluten interactions played major roles in imparting the desired functionality of the model dough. A possible interaction model between partially gelatinized potato starch and gluten was proposed. Partially gelatinized potato starch with moderate degree of gelatinization could more closely interact with gluten, better improve the texture and processing adaptability of model dough than native and highly gelatinized starch, thus has promising application potential in food industry.

Effects of particle size distribution of potato starch granules on rheological properties of model dough underwent multiple freezing-thawing cycles.

In order to elucidate the mechanism underlying the effect of different-sizes potato starch on dough during freeze-thaw treatment, the rheological properties, moisture distribution, secondary structure, and relative crystallinity of dough were investigated. The results showed that the storage modulus (G'), loss modulus (G″), and complex modulus (|G*|) of dough increased as a result of the freeze-thaw treatment, and the effect was more obvious as the starch granular sizes increased. The higher ß -sheet and T22 contents reflected the higher viscoelasticity and freeze-thaw sensitivity, which may be related to the higher degree expansion of amylose. In contrast, dough with small-sized starch had higher intermolecular interactions, and denser structure, lower water migration, showing that this has better resistance and higher stability. The presented mechanisms may contribute to the better understanding of the effects of freeze-thaw process on model dough properties.

Dynamic changes of potato characteristics during traditional freeze-thaw dehydration processing.

An ancient folk technology of freeze-thaw processing had been simulated by studying the dehydration efficiency of potatoes using different freezing rates (0.02, 0.06, 0.08, 0.11, 0.20 and 0.40 °C/min). The results showed that the dehydration rate was negatively correlated to freezing rates at a range of 35.66% to 53.85%. Better dehydration efficiency (41.71%) with relatively more protein (83.66%) and mineral retention was obtained at the medium freezing rate of 0.11 °C/min. On this condition, the internal and external pressures of potato cells were balanced and the reduction of immobilized water (T22) was significantly higher compared to that at other conditions. The untargeted metabolomic results showed that some lipids, organic acids and amino acids in potatoes were affected by freezing treatment. The dynamic changes of potato characteristics during freeze-thaw processing gained in this research could be employed as a foundation for diversified applications of dehydrated potatoes.

Effect of high-intensity ultrasound on the structural, rheological, emulsifying and gelling properties of insoluble potato protein isolates.

The denaturation and lower solubility of commercial potato proteins generally limited their industrial application. Effects of high-intensity ultrasound (HIU) (200, 400, and 600 W) and treatment time (10, 20, and 30 min) on the physicochemical and functional properties of insoluble potato protein isolates (ISPP) were investigated. The results revealed that HIU treatment induced the unfolding and breakdown of macromolecular aggregates of ISPP, resulting in the exposure of hydrophobic and R-SH groups, and reduction of the particle size. These active groups contributed to the formation of a dense and uniform gel network of ISPP gel and insoluble potato proteins/egg white protein (ISPP/EWP) hybrid gel. Furthermore, the increase of solubility and surface hydrophobicity and the decrease of particle size improved the emulsifying property of ISPP. However, excessive HIU treatment reduced the emulsification and gelling properties of the ISPP. Meanwhile, HIU treatment changes the secondary structure of ISPP. It could be speculated that the formation of a stable secondary structure of ISPP initiated by cavitation and shearing effect might play a dominant role on gel strengthens and firmness. Meanwhile, the decrease in relative content of ß-turn had a positive effect on the formation of small particle to improve emulsifying property of ISPP.

Rheological behaviors and physicochemical changes of doughs reconstituted from potato starch with different sizes and gluten.

The effects of different sizes of potato starch on the rheological and physiochemical properties of model doughs were investigated. Compared with those of model dough prepared from original starch, the strengths of model doughs prepared from fractionated starch were higher, which indicates that fractionated starch can positively influence the properties of doughs. Additionally, the model dough prepared using large size starch granules had higher storage modulus (G'), loss modulus (G''), and composite modulus (|G*|) values compared to those of other types of dough; it also had the highest elasticity, viscosity, and strength. This might be related to its high amylose content (20.28 ± 0.69%) and high 1045 cm-1/1022 cm-1 ratio (1.27 ± 0.17). The model dough (S) prepared from starch with small sizes had the highest contents of disulfide bonds (2.91 µmolg-1), ß-turn (33.92 ± 1.17%), and ß-sheet (22.57 ± 0.54%); and it also had better network structure and dough stability. Thus, the stability of the S model dough was affected by phosphorus (1194.57 ± 25.32 ppm) and amylopectin (84.19 ± 1.88%) content, and, moreover, by the competition for water. Stability and network structure of dough are relative to the size distribution of starch granules. Finally, a schematic model showing the mechanism of the influence of phosphorus, sulfhydryl, and disulfide bonds in fractionated starch on the rheological properties of dough was developed.

Potato resistant starch inhibits diet-induced obesity by modifying the composition of intestinal microbiota and their metabolites in obese mice.

Potato resistant starch type 3 (PRS) is helpful for weight-loss. To investigate the regulatory effects of PRS on high-fat diet (HFD)-induced obesity, different doses of PRS (5%, 15% and 25%) were fed to mice for 12 weeks. Metabolic syndrome related to obesity, intestinal microbiota composition and its metabolites as well as the relationship among them were studied. Results showed that PRS could regulate HFD-induced metabolic syndrome in a dose dependent manner; promote the proliferation of intestinal cells and expression of tight junction proteins, such as Occludin and zonula occludens (ZO)-1; reduce the Firmicutes/Bacteroidetes (F/B) rate; regulate the relative abundance of intestinal microbiota, such as Bifidobacterium, Ruminococcus, Bacteroides and Coprococcus; and promote the production of microbial metabolites, such as propionic acid and acetic acid. Besides, the alteration in the intestinal microbiota composition and metabolites were significantly correlated. It could be concluded that propionic acid and acetic acid were the two dominant metabolites of Bifidobacterium, Ruminococcus, Bacteroides, and Coprococcus, which contributed to the anti-obesity potential of PRS, metabolic syndrome alleviation, and intestinal barrier dysfunction.

Comparative Study of the Nutritional Properties of 67 Potato Cultivars (Solanum tuberosum L.) Grown in China Using the Nutrient-Rich Foods (NRF11.3) Index.

The overall nutritional properties of tubers from 67 potato cultivars were systematically evaluated in this study by adopting the Nutrient-Rich Foods (NRF11.3) Index Model. The macronutrients including dry matter, crude protein, total dietary fiber, and starch contents were found to be in the range of 14.8-30.5 g/100 g fresh weight, 5.71-12.0, 1.99-3.39, and 56.0-75.5 g/100 g dry weight, respectively. Additionally, the amounts of vitamin C, K and Fe were 22.6-86.6, 1457-3111, and 1.40-5.06 mg/100 g dry weight, respectively. The NRF11.3 index model has a score of 66.4-102 per 100 kcal for male and 70.8-107 per 100 kcal for female over 18 years old. This model was utilized to determine the macrocomponents and micronutrients of diverse potato cultivars and aid in comprehensive nutritional study on potato as a desirable raw material for staple food processing to human nutrition and daily intake.

Adaptation response of Pseudomonas fragi on refrigerated solid matrix to a moderate electric field.

BACKGROUND: Moderate electric field (MEF) technology is a promising food preservation strategy since it relies on physical properties-rather than chemical additives-to preserve solid cellular foods during storage. However, the effectiveness of long-term MEF exposure on the psychrotrophic microorganisms responsible for the food spoilage at cool temperatures remains unclear. RESULTS: The spoilage-associated psychrotroph Pseudomonas fragi MC16 was obtained from pork samples stored at 7 °C. Continuous MEF treatment attenuated growth and resulted in subsequent adaptation of M16 cultured on nutrient agar plates at 7 °C, compared to the control cultures, as determined by biomass analysis and plating procedures. Moreover, intracellular dehydrogenase activity and ATP levels also indicated an initial effect of MEF treatment followed by cellular recovery, and extracellular ß-galactosidase activity assays indicated no obvious changes in cell membrane permeability. Furthermore, microscopic observations using scanning and transmission electron microscopy revealed that MEF induced sublethal cellular injury during early treatment stages, but no notable changes in morphology or cytology on subsequent days. CONCLUSION: Our study provides direct evidence that psychrotrophic P. fragi MC16 cultured on nutrient agar plates at 7 °C are capable of adapting to MEF treatment.

An L-type calcium channel agonist, bay K8644, extends the window of intervention against ischemic neuronal injury.

Our previous data indicate that the inhibition of L-type calcium channels (LTCCs) might be the cause of post-ischemic neuronal injury and that the activation of LTCCs can give rise to neuroprotection. In the present study, we aimed to profile the intervention window of Bay K8644, an LTCC agonist, and determine the involved mechanisms. The four vessel occlusion and oxygen-glucose deprivation models were employed to mimic ischemia/reperfusion damage in vivo and in vitro. Neuronal injury was analyzed using Nissl and Fluoro-Jade B staining in vivo and Hoechst 33342 and propidium iodide staining in vitro. The behavioral effects were tested using the Morris water maze. The phosphorylation of P38, Jun N-terminal kinase, and extracellular-regulated kinase (ERK) was detected by Western blotting. Our results show that Bay K8644 administered as late as 24 h after reperfusion prevented CA1 neuronal death and ameliorated the deficiencies in spatial learning performance induced by global ischemia. In oxygen-glucose deprivation (OGD), Bay K8644 delivered from 1 to 12 h after re-oxygenation reduced neuronal death. The decrease in p-ERK1/2 that was observed at 1 h after OGD was reversed by Bay K8644, and the effect of Bay K8644 was blocked by treatment with U0126 and MEK kinase dead transfection. Moreover, similar to Bay K8644, FPL 64176, another potent LTCC agonist, extends the window of intervention against neuronal injury in an in vitro model of ischemia. In conclusion, our data suggest that opening LTCCs may be a practicable approach for stroke therapy.

Suffruyabiosides A and B, two new monoterpene diglycosides from moutan cortex.

Two new monoterpene diglycosides, suffruyabiosides A and B, and seven known compounds 3-9 were isolated from Moutan Cortex (root cortex of Paeonia suffruticosa Andrews). The structures were elucidated on the basis of 2D NMR spectral data. Suffruyabiosides A and B are rare monoterpene diglycosides, including a cellobiose in the molecules. Salicylpaeoniflorin (4) had a antiproliferation effect similar to paeoniflorin (3) on human lung adenocarcinoma epitherial A549 cells. Galloylpaeoniflorin (8) and salicylpaeoniflorin (4) revealed a more pronounced radical scavenging effect than a-tocopherol (positive control). An increase in the number of phenolic hydroxyl groups produced a more effective radical scavenging effect [8 > mudanpioside E (6) > oxypaeoniflorin (5)]. Comparison of the effects of 4 and 5 showed that o-substitution with a phenolic hydroxyl group was more effective than p-substitution. The results suggest that salicylpaeoniflorin (4) may be useful as a cytotoxic and a radical scavenging agent.

Antioxidant and antitumor activities of water extracts from the root of Actinidia kolomikta.

The genus of Actinidia is widely distributed throughout the Asian continent. Specific Actinidia species have been used as health foods and medical products for cancer treatment. Actinidia kolomikta is a species of wild plant that grows in the northern part of Indochina. However, few studies on its bioactivity have been reported. In this study, the polysaccharide and polyphenol contents, the SOD-like activity and the DPPH radical-scavenging activity of water extracts from the root of Actinidia kolomikta produced under different extraction temperatures were investigated. Furthermore, the water extraction-ethanol precipitate (WE-EP) fraction and the water extraction-ethanol supernatant (WE-ES) fraction were used to test the anti-proliferative action on DLD-1 colon cancer cells. Extracts produced using the 100°C extraction procedure revealed higher extraction yields and antioxidant activities than extracts produced using the 40°C extraction procedure. The WE-EP and WE-ES fractions exhibited anti-proliferative effects on the DLD-1 cells. Moreover, the WE-ES polyphenol-enriched fraction possessed more potent anti-proliferative effects on the DLD-1 cells by inducing apoptosis compared to the WE-EP polysaccharide fraction. Medicinal plant extracts are generally considered to be relatively non-toxic at low doses and are not thought to cause major side effects compared to those observed with drugs. Wild A. kolomikta may provide an alternative to currently employed cancer therapies, and may be used as a natural health food with antioxidant actions.

Antitumor effect of extracts from moutan cortex on DLD-1 human colon cancer cells in vitro.

Moutan cortex, the root bark of Paeonia suffruticosa Andrews (Paeoniaceae), is a traditional Chinese medicine widely used for the treatment of various diseases. In the present study, we examined the antiproliferative effect and apoptosis-inducing activity of paeonol and the crude total glycosides (CTG) extracted from moutan cortex against DLD-1 human colon cancer cells in vitro. Cell viability was measured using the WST-8 assay. Apoptosis was detected by Hoechst 33258 fluorescence staining and flow cytometry. Paeonol and the CTG significantly reduced cell viability in a dose- and time-dependent manner. The induction of apoptosis in DLD-1 cells was characterized by morphological changes and an increased percentage of hypodiploid cells. After treatment for 48 h with paeonol (400 µg/ml) or CTG (200 µg/ml), the ratio of apoptotic cells reached 34.79 and 48.12%, respectively. The findings obtained indicate that paeonol and the CTG extracted from moutan cortex have a significant growth-inhibitory effect on human colon cancer cells. This effect may be related to the induction of apoptosis.

Neuroprotective effects of xiao-xu-ming decoction against ischemic neuronal injury in vivo and in vitro.

ETHNOPHARMACOLOGICAL RELEVANCE: Xiao-Xu-Ming decoction (XXMD) has long been employed clinically to treat stroke in traditional Chinese Medicine. AIM OF THE STUDY: To investigate the neuroprotective effects of XXMD in vivo and in vitro stroke models and determine involved mechanisms. MATERIALS AND METHODS: Two models (four-vessel occlusion in adult Wistar rats and oxygen-glucose deprivation primary cultured neurons) were employed to mimic ischemia-reperfusion damage, in vivo and in vitro, respectively. The effects of XXMD were investigated with respect to neuronal damage, activity of caspase-3 and expression of Bcl-2 in CA1 region of hippocampus after ischemia. The cognitive ability was measured 7 days after ischemia/reperfusion by using Morris water maze. RESULTS: Oral administration of XXMD significantly increased the density of neurons that survived in the CA1 region of hippocampus on the 3rd and 7th day after transient global ischemia was induced in a dose-dependent manner. XXMD ameliorated severe deficiencies in spatial cognitive performance induced by transient global ischemia. Inhibition of caspase-3 activity and up-regulation of Bcl-2 expression were induced in the high dose of XXMD-treated rats after ischemia. In oxygen-glucose deprivation model, both XXMD extract and drug-containing serum prepared from blood of high dose of XXMD-treated rats inhibited apoptotic neuronal death at 24h after reoxygenation. CONCLUSIONS: Our results clearly demonstrated that XXMD is neuroprotective and appears to influence deleterious pathological processes that are activated after the onset of ischemia.