Dietary resistant starch alleviates Escherichia coli-induced bone loss in meat ducks by promoting short-chain fatty acid production and inhibiting Malt1/NF-κB inflammasome activation

Background:Escherichia coli(E.coli)infection in humans and animals usually comes with gut dysbiosis,which is potential culprit to skeletal health,it is still unclear to whether diet interfered gut microbiome changes can be a protective strategy to bone loss development.Here,the effects of resistant starch from raw potato starch(RPS),a type of prebiotic,on E.coli-induced bone loss and gut microbial composition in meat ducks were evaluated.Results:The results showed that dietary 12%RPS treatment improved bone quality,depressed bone resorption,and attenuated the pro-inflammatory reaction in both ileum and bone marrow.Meanwhile,the 12%RPS diet also increased the abundance of Firmicutes in E.coli-treated birds,along with higher production of short-chain fatty acids(SCFAs)especially propionate and butyrate.Whereas addition ofβ-acid,an inhibitor of bacterial SCFAs production,to the drinking water of ducks fed 12%RPS diet significantly decreased SCFAs level in cecum content and eliminated RPS-induced tibial mass improvement.Further,treatment with MI-2 to abrogate mucosa-associated lymphoid tissue lymphoma translocation protein 1(Malt1)activity replicated the protective role of dietary 12%RPS in E.coli-induced bone loss including reduced the inhibition on nuclear factorκB(NF-κB)inflammasome activation,decreased bone resorption,and improved bone quality,which were correlated with comparable and higher regulatory T cells(Treg)frequency in MI-2 and 12%RPS group,respectively.Conclusions:These findings suggested that the diet with 12%RPS could alleviate E.coli-induced bone loss in meat ducks by changing the gut microbial composition and promoting concomitant SCFAs production,and consequently inhibiting Malt1/NF-κB inflammasome activation and Treg cells expansion.

RVA and Farinograph Properties Study on Blends of Resistant Starch and Wheat Flour

Resistant starch （RS） is the undigested starch that passes through the small intestine to the large intestine. As a functional low calorie additive, it has special applications in the food industry. Rapid visco analysis （RVA） and the Brabender farinograph were used to study the pasting properties and the viscoelasticity of blends of RS （RS3 and RS2） and three wheat flours. The wheat flours represented strong gluten wheat （SGW）, intermediate gluten wheat （IGW）, and weak gluten wheat （WGW） flours, at different levels of RS substitution （0, 5, 10, 15, and 20%）. The influence of RS3 on the control wheat flours and RS-wheat flour blends were consistent with those of RS2. The peak, trough, and final viscosities of RS3-wheat flour blends were higher than those of the corresponding RS2-wheat flour blends. The peak, trough, breakdown, final, and setback viscosities ofwheat-RS blends decreased with an increase in resistant starch contents from 0 to 20% in the blends. The 0-20% RS-wheat flour blends were all able to form doughs. The dough development times, dough stabilities, dough breakdown times, and farinograph quality numbers for the RS-wheat flour blends decreased as the RS proportion in the blends increased. The values for RS-SGW flour blends were the highest, followed by RS-IGW and then RS-WGW flour blends. The water absorption values for RS-wheat flour blends and the mixing tolerance index for RS-WGW flour blends were found to increase significantly with an increasing proportion of RS from 0 to 20%, but the mixing tolerance index for RS-SGW and RS-IGW flour blends showed no significant differences amongst the different ratios. Correlation analysis showed that the Farinograph quality number was highly positively correlated with dough breakdown time, dough stability, and dough development time （r= 1.000, 0.958, 0.894）, and highly negatively correlated with the mixing tolerance index （r =-0.890）. Data from this study can be used for the development of dough-based products. It also provides a basis for RS-wheat flour blends and quality evaluation in the food industry.

Effect of Dietary Resistant Starch on Prevention and Treatment of Obesity-related Diseases and Its Possible Mechanisms

Overweight or obesity has become a serious public health problem in the world, scientists are concentrating their efforts on exploring novel ways to treat obesity. Nowadays, the availabilities of bariatric surgery and pharmacotherapy have enhanced obesity treatment, but it should has support from diet, physical exercise and lifestyle modification, especially the functional food. Resistant starch, an indigestible starch, has been studied for years for its beneficial effects on regulating blood glucose level and lipid metabolism. The aim of this review is to summarize the effect of resistant starch on weight loss and the possible mechanisms. According to numerous previous studies it could be concluded that resistant starch can reduce fat accumulation, enhance insulin sensitivity, regulate blood glucose level and lipid metabolism. Recent investigations have focused on the possible associations between resistant starch and incretins as well as gut microbiota. Resistant starch seems to be a promising dietary fiber for the prevention or treatment of obesity and its related diseases.

Physiochemical Properties of Resistant Starch and Its Enhancement Approaches in Rice

With changes in food preferences and life styles,more and more attentions have been focused on healthier food.Nowadays,resistant starch(RS)which can resist digestion in the human intestine has been recognized and accepted.High RS diet shows great benefit for the human health,and breeding high RS rice variety is a great target for realizing dietary intervention.To provide guidance for RS improvement in rice,this review summarized the unique physiochemical properties of RS and the possible approaches,i.e.genetic regulation,for enhancing RS content in rice,and proposed the potential ways to obtain rice variety with high RS content.

Resistant starch: Implications of dietary inclusion on gut health and growth in pigs:a review

Starch from cereal grains,pulse grains,and tubers is a major energy substrate in swine rations constituting up to 55%of the diet.In pigs,starch digestion is initiated by salivary and then pancreaticα-amylase,and has as final step the digestion of disaccharides by the brush-border enzymes in the small intestine that produce monosaccharides(glucose)for absorption.Resistant starch(RS)is the proportion of starch that escapes the enzymatic digestion and absorption in the small intestine.The undigested starch reaches the distal small intestine and hindgut for microbial fermentation,which produces short-chain fatty acids(SCFA)for absorption.SCFA in turn,influence microbial ecology and gut health of pigs.These fermentative metabolites exert their benefits on gut health through promoting growth and proliferation of enterocytes,maintenance of intestinal integrity and thus immunity,and modulation of the microbial community in part by suppressing the growth of pathogenic bacteria while selectively enhancing beneficial microbes.Thus,RS has the potential to confer prebiotic effects and may contribute to the improvement of intestinal health in pigs during the post-weaning period.Despite these benefits to the well-being of pigs,RS has a contradictory effect due to lower energetic efficiency of fermented vs.digested starch absorption products.The varying amount and type of RS interact differently with the digestion process along the gastrointestinal tract affecting its energy efficiency and host physiological responses including feed intake,energy metabolism,and feed efficiency.Results of research indicate that the use of RS as prebiotic may improve gut health and thereby,reduce the incidence of post-weaning diarrhea(PWD)and associated mortality.This review summarizes our current knowledge on the effects of RS on microbial ecology,gut health and growth performance in pigs.

Application of resistant starch in bread: processing, proximate composition and sensory quality of functional bread products from wheat flour and African locust bean <i>(Parkia biglobosa)</i>flour

Application of resistant starch prepared from parkia flour was produced by replacement of wheat flour with 0, 5%, 10%, 15%, 20%, 30% and 40% Parkia flour. Processing, proximate composition, digestibility of resistant starch in bread and sensory quality were evaluated. Resistant starch was significantly (p < 0.05) increased as Parkia flour level increase in all breads. The resistant starch prepared from Parkia flour was 47.21%. However, wheat bread was 1.47% and Parkia bread 18.52% to 22.28% baked of (200℃ at 45 min) with 2.16% wheat bread and 31.74% to 35.05% Parkia bread baked of (130℃ at 90 min). Supplementation of wheat flour with Parkia flour 0 - 40% increased the crude protein content significantly (p < 0.05) from (7.89% - 15.68%), ash from (0.91% - 2.54%) and crude fiber (1.41% - 4.97%). Color of the bread treatments was remarkably affected by addition of different levels of Parkia flour. Therefore, Parkia flour could be added to wheat flour up to 15% without any observed detrimental effect on bread sensory properties. Sensory evaluation results indicated that bread with 5% to15% Parkia flour were rated the most acceptable and there was no significant difference in terms of acceptability compared to the control. This could be used to improve the nutritional quality of bread especially in developing countries were malnutrition is prevalent.

Thermo-Mechanical Properties Study of Stabilized Soil Bricks to Sugar Cane Molasses and Cassava Starch Binders

The current study deals Swith thermo-mechanical properties of stabilized soil small bricks with the help of organic binders of sugar cane molasses and cassava starch. Different formulations of soil concrete have been suggested after the geotechnical characterization of samples of soil was taken. From these, it arises that the studied soil is the most plastically clay (of type A3) according to GTR classification. Samples made of small bricks and measured out at 4%, 6% and 8% of binders (molasses, starch or molasses + starch) have been warmed up to different temperatures (100°C, 150°C, 200°C and 250°C) for the rising of the thermic behavior under different conditions and submitted to crushing testings for the estimation of characteristic resistances to the compression. According to the mechanical behavior, we note an improvement of resistances for small bricks measured 4%, 6% and 8%, of molasses respectively of 32.44%, 32.06% and 23.43% against the value of reference for small bricks without molasses. In the same way, the binder (molasses + starch) also reveals an improvement of resistance to the compression of 13.27%, 26.17% and 26.17%. On the contrary, the stabilization with the starch binder did not bring a significative improvement. According to the thermic influence, the heating at 100°C of stabilized small bricks at 4%, 6% and 8% of molasses, reveals a significative improvement of resistances. Moreover, the stabilization with the starch reveals on the contrary a good behavior for heatings at 150°C and 250°C. In short, for the binder (molasses + starch), it is the heating at 200°C that shows some improvements of remarkable resistances. Different analyses of realized statistics also show the effectivity of obtained results. For all realized formulations, the measuring out at 6% of binders (molasses, or molasses + starch) seems as optimal in front of the best thermo-mechanical revealed properties.

Structural Characteristics of Semen coicis Resistant Starch and Its Effect on the Proliferation of Bifidobacterium bifidum

Semen coicis resistant starch is a type of starch which has undergone retrogradation. In this study,the structural characteristics of Semen coicis native starch,high-amylose maize starch,and heat-moisture treated Semen coicis resistant starch were investigated. The field emission scanning electron microscopy results indicated that compared to Semen coicis native starch and high-amylose maize starch,the surface of heat-moisture treated Semen coicis resistant starch was rough and full of irregular layered strips. The Fourier transform infrared spectroscopy measurements indicated the degree of ordered structure values of Semen coicis native starch,high-amylose maize starch,and heat-moisture treated Semen coicis resistant starch are 1.355,1.372,and 1.410,respectively,and the degree of double helix values is 1.931,1.942,and 2.027,respectively,indicating that the degree of ordered structure and double helix structure of heat-moisture treated Semen coicis resistant starch is both higher than those of Semen coicis native starch and high-amylose maize starch. ^（13） C nuclear magnetic resonance spectroscopy showed that Semen coicis native starch and high-amylose maize starch exhibited A-type crystal structures,while heat-moisture treated Semen coicis resistant starch displayed B-type crystal structures. The relative crystallinity of Semen coicis native starch,high-amylose maize starch,and heat-moisture treated Semen coicis resistant starch is 76.41,85.36,and 87.25,respectively,and the percentages of amorphous region are 5.78,4.72,and 4.39,respectively. Additionally,heat-moisture treated Semen coicis resistant starch could increase the proliferation of Bifidobacterium bifidum more than Semen coicis native starch or high-amylose maize starch. Bifidobacterium bifidum displayed a higher tolerance under simulated gastrointestinal tract conditions such as low p H,bile acid,pepsin,and trypsin in heat-moisture treated Semen coicis resistant starch medium than in Semen coicis native starch or high-amylose maize starch media.

Starch Grafted Water Resistant Polyvinyl Acetate-Based Wood Adhesive: A Review

Global energy issues and the reliance on hydrocarbon resources have resulted in the reduction of petroleum sources, and the focus of the chemical industries has shifted to substitute raw material sources. The major raw materials used in wood adhesives, such as hydrocarbons like polyvinyl acetate, would be gradually replaced by renewable natural polymers. Currently, polyvinyl alcohol has the limitation of petroleum origin, which is non-economical and it will be replaced by biopolymers. Conventionally available wood adhesive emulsions are colloid-like polyvinyl alcohol stabilized. Starch, being a naturally available polymer, has gained interest from researchers for replacing polyvinyl alcohol as a stabilizer. New research on sustainable, economical, biodegradable, renewable, and environmentally friendly starch grafted polyvinyl acetate emulsion that was synthesized by the graft polymerization of vinyl acetate monomer onto starch. However, starch grafted polyvinyl acetate emulsion-based adhesive’s properties, such as poor water resistance, weak adhesion, delayed drying rate and delayed setting speed, have resulted in limitations in its application as a wood adhesive. A detailed review of starch grafting on vinyl acetate and comonomers like acrylamides, and acrylic acid, and the addition of nano-fillers to enhance the water resistance and performance properties of sustainable adhesives has been explained.

Chronic Physical Activity Does Not Impact Metabolic Responses to Low or High Doses of Resistant Starch: A Crossover Trial

Physical activity and resistant starch are known independently, to beneficially affect metabolic health especially in the gut. However, little is known about the combined effects of physical activity and resistant starch. Thus, the purpose of this study was to investigate the effects of physical activity at different dosages of resistant starch on gut and metabolic health, represented by breath hydrogen and blood glucose responses. Twenty young, healthy participants were stratified into two physical activity groups based on seven-day accelerometry data. Participants visited the lab twice in random order and consumed a meal with either 5 g or 25 g of resistant starch. Breath hydrogen and blood glucose were measured at baseline and serially for six and two hours after meal consumption respectively. Total area under the curve (AUC) for breath hydrogen and incremental AUC for blood glucose were not different between physical activity groups or resistant starch conditions. Thus, chronic physical activity status did not impact breath hydrogen or blood glucose responses to either low or high resistant starch meals.

Dietary resistant starch ameliorating lipopolysaccharide-induced inflammation in meat ducks associated with the alteration in gut microbiome and glucagon-like peptide 1 signaling

Background:Consumption of resistant starch(RS)has been associated with various intestinal and systemic health benefits,but knowledge of its effects on intestinal health and inflammatory response in stressed birds is limited.Here,we examined how dietary RS supplementation from 12%raw potato starch(RPS)modulated inflammatory severity induced by lipopolysaccharide(LPS)in meat ducks.Results:LPS administration at 14,16,and 18 d(chronic challenge)decreased body weight(BW)and glucagon-like peptide 1 receptor(GLP-1R)level with higher intestinal permeability and inflammation,evident by higher proinflammatory cytokine levels.Dietary 12%RPS supplementation enhanced Claudin-1 and GLP-1R expression,along with lower levels of inflammatory factors in both ileum and serum.Microbiome analysis showed that RS treatment shifted microbial structure reflected by enriched the proportion of Firmicutes,Bifidobacterium,Ruminococcus,etc.Dietary RS addition also significantly increased the concentrations of propionate and butyrate during chronic LPS challenge.Furthermore,response to acute challenge,the ducks received 2 mg/kg BW LPS at 14 d had higher concentrations of serum endotoxins and inflammatory cytokines,as well as upregulated transcription of toll like receptor 4(TLR4)in ileum when compared to control birds.Analogous to GLP-1 agonist liraglutide,dietary RS addition decreased endotoxins and inflammation cytokines,whereas it upregulated the GLP-1 synthesis related genes expression.Meanwhile,dietary RS supplementation suppressed the acute LPS challenge-induced TLR4 transcription.Conclusions:These data suggest that dietary 12%RPS supplementation could attenuate the LPS-induced inflammation as well as intestinal injury of meat ducks,which might involve in the alteration in gut microbiota,SCFAs production and the signaling pathways of TLR4 and GLP-1/GLP-1R.

Effect of Several Common Processing Methods on Content Changes of Resistant Starch and Main Nutrients in ‘Luotian Chestnut’

Using ＇Luotian chestnut＇ as the raw material, the content changes of resistant starch and main nutrients in the processed fruit were studied after taken common processing of high-temperature steaming of canned food, sand-mixed frying and cooking without shells, with the aim to find out the effects of different processing methods on the content changes of nutrients in chestnuts. The result showed that there were significant differences in the resistant starch contents by different processing methods. After processing, the retention degree of resistant starch was the lowest using the methods of sand-mixed frying, of 42.42%, while the highest was found in canned chestnut products, of 93.16%. Among the main nutrients, adding water and sugar would reduce content of resistant starch, while increasing the protein content would promote the retention of resistant starch retention. The changes in lipid content had no effect or not a single promoting or weakening effects on the content of resistant starch.

Preparation and characterization of resistant starch type 3 from yam and its effect on the gut microbiota

Background:Yam(Dioscorea opposita Thunb.)has been consumed as a food and used in traditional Chinese medicine for thousands of years.Resistant starch(RS)3 is of particular interest because it is heat-resistant,safe and non-toxic,and retains good nutritional benefits;it is therefore used in a wide range of traditional and emerging foods as a heat-stable prebiotic ingredient.In our previous study,we found that yam RS includes strong lipid-lowering and anti-constipation activities.Methods:Yam RS3 was prepared by autoclaving-retrogradation and pullulanase debranching to yield autoclaving-retrogradation yam RS and pullulanase debranching yam RS,respectively.First,the physicochemical properties of both RS3s were analyzed.Second,the structures of the RS3s were characterized by scanning electron microscopy,X-ray powder diffraction,and Fourier transform infrared spectroscopy.Finally,the regulatory effects of the RS3s on the gut microbiota were evaluated using an in vitro fecal fermentation model.Results:The RS content of the RS3s decreased after processing,but was higher in pullulanase debranching yam RS(35.67%)than in autoclaving-retrogradation yam RS(28.71%).Compared with native yam starch,RS3s lost their original granular shapes and instead exhibited irregularly shapes with continuous phases.The crystalline structure of the RS3s was completely altered,with pullulanase debranching yam RS exhibiting B-type patterns.Both RS3s,and especially pullulanase debranching yam RS,promoted a significant increase in short chain fatty acid content after in vitro fermentation(all P<0.05).Moreover,pullulanase debranching yam RS significantly increased the abundance of beneficial bacteria and decreased the abundance of harmful bacteria such as Escherichia and Shigella(all P<0.05).Conclusion:Our findings show that yam RS3s can regulate the composition of the gut microbiota and promote the production of short chain fatty acid,especially butyric acid.Pullulanase debranching was a more effective method for producing functional yam RS3.

Hygroscopicity-resistant mechanism of an α-starch based composite binder for dry sand molds and cores

Hygroscopicity-resistance of an α-starch based composite binder for dry sand molds (cores) has been studiedexperimentally and theoretically. Focus is placed on the relationship between the hardening structure andhumidity-resistance of the composite binder. The results show that the α-starch composite binder has goodhumidity-resistance due to its special complex structure. SEM observations illustrate that the composite binder consists ofreticular matrix and a ball- or lump-shaped reinforcement phase, and the specific property of the binding membrane withheterogeneous structure is affected by humidity to a small extent. Based on the analyses on the interplays of differentingredients in the binder at hardening, the structure model and hygroscopicity-resistant mechanisms of the hardeningcomposite binder were further proposed. Moreover, the reasons for good humidity-resistance of the composite binderbonded sand are well explained by the humidity-resistant mechanisms.

脱支酶解-压热法制备淮山薯RS3抗性淀粉的工艺优化及体外消化模拟评价

以淮山薯为原料,通过脱支酶解-压热法制备RS_(3)抗性淀粉。以抗性淀粉得率为指标,在单因素试验的基础上通过正交试验优化制备工艺,并通过体外消化模拟试验评价RS_(3)抗性淀粉的消化性能。结果表明:最佳制备工艺为淀粉乳质量分数25%、普鲁兰酶添加量200 U/g(以干基淀粉质量计)、酶解时间12 h、老化时间18 h,在此条件下RS_(3)抗性淀粉得率为16.95%±0.22%;淀粉还原糖释放量为11.35%±0.20%,RS_(3)抗性淀粉还原糖释放量为8.42%±0.14%(P<0.05),表明RS_(3)抗性淀粉比淀粉抗消化能力更强。

物理法制备RS3型抗性淀粉的研究进展

抗性淀粉是指在健康人体小肠不被消化和吸收的多糖类物质,对人体健康有益。回生淀粉(RS3)作为抗性淀粉的其中一类,因具有热稳定性好、持水性低等特点,在食品工业中被广泛应用。本文分别综述了近年来超声法、微波法、湿热法以及韧化法制备RS3型抗性淀粉对其得率、理化性质和结构的影响,并对物理法制备RS3型抗性淀粉的现状提出展望,以期为物理法制备RS3型抗性淀粉的研究提供有益的参考,促进物理法制备抗性淀粉的实际应用。

Decay Resistance of Particleboards Manufactured with Four Agro-Forest Residues Using Cassava Starch and Urea Formaldehyde as Adhesives

Many factors including depletion of the forest, environmental awareness, and generation of large quantities of agro-forest residues have increased the need to partially or wholly replace wood with agro-forest residue for particleboard production. This study assessed the decay resistance of particleboards produced from four agro-forest residues using cassava starch and urea formaldehyde as adhesives. Musa paradisiaca pseudostem, Theobroma cacao stem and pod, and sawdust of Ceiba pentandra were used for the study. Properties determined were: Weight loss, decay resistance rating and decay susceptibility index. These properties were evaluated after 12 weeks of exposure to Coriolopsis polyzona in accordance with ASTM D 2017-05. The results indicate that the weight loss for Musa paradisiaca pseudostem particleboard was least for both urea formaldehyde and cassava starch adhesives. Even though almost all the particleboards produced were classified as resistant or highly resistant to fungi attack, those produced with urea formaldehyde had better decay resistance properties than that of cassava starch. Furthermore, particleboards coated with synthetic polyvinyl lacquer had better resistance to fungi attack than the uncoated ones. At 5% level of significance, the agro-forest residue, adhesive and surface finish as well as their interactions had significant effects on decay resistance of the particleboards produced. It is recommended that further studies which aim at determining the effect of combination of the agro-forest residues and that of urea formaldehyde and cassava starch be conducted to determine their effects on decay properties of particleboards.

Biodegradation Behavior of Starch in Simulated White Water System of Old Corrugated Cardboard Pulping Process

Considering the serious barriers/issues induced by the accumulated starch generated in white water system of old corrugated cardboard(OCC)pulping process,large amounts of accumulated starch in white water would be decomposed by microorganisms and could not be utilized,thereby resulting in severe resource wastage and environmental pollution.This study mainly explored the effects of biodegradation/hydrolysis conditions of the two types of starch substrates(native starch and enzymatically(α-amylase)hydrolyzed starch),which were treated via microorganism degradation within the simulated white water from OCC pulping system and their biodegradation products on the key properties were characterized via X-ray diffraction(XRD),Fourier-transform infrared spectroscopy(FT-IR),and gel permeation chromatography(GPC)technologies.The effects of system temperature,pH value,starch concentration,and biodegradation time on starch biodegradation ratio and the characteristics of obtained biodegradated products from the two types of starches were studied.In addition,the effect ofα-amylase dosage on the biodegradation ratio of enzymatically hydrolyzed starch and its properties was investigated.It was found that the native starch presented a maximal degradation ratio at a system temperature of 55℃and pH value range of 5-7,respectively,the corresponding starch concentration within simulated white water system was 200 mg/L.Whereas the enzymatically hydrolyzed starch exhibited a highest degradation ratio at a system temperature of 50℃and pH value of 5.5,respectively,and the corresponding starch concentration within simulated white water system was 100 mg/L.It was verified that native starch is more readily bio-hydrolyzed and biodegradation-susceptive by microorganisms in simulated white water system of OCC pulping process,while the enzymatically hydrolyzed starch exhibits better biodegradation/hydrolysis resistance to the microbial degradation than that of native starch.This study provides a practical and interesting approach to investigate the starch hydrolysis or biodegradation behaviors in white water system of OCC pulping process,which would greatly contribute to the full recycling and valorized application of starch as a versatile additive during paperboard production.

基于商用芭蕉芋RS3型抗性淀粉碳源的菌株筛选、分离与功能性评价

目的筛选、鉴定和功能性评价优势酵解商用芭蕉芋RS3型抗性淀粉的健康人体肠道菌,为商用芭蕉芋RS3型抗性淀粉合生元制剂提供高价值菌种。方法采用商用芭蕉芋RS3型抗性淀粉改良BHI固体培养基,筛选并鉴定优势酵解肠道菌,用DPPH自由基清除实验和ABTS自由基清除实验考察菌株抗氧化能力,用溶血性实验和药敏实验评价其安全性。结果菌株1-6和菌株S1能够发酵商用芭蕉芋RS3型抗性淀粉并显著降低体系pH值(P<0.05),经鉴定均为蜡样芽孢杆菌。两种菌株无细胞提取上清液对DPPH自由基清除率分别79.63%和51.56%,对ABTS自由基清除率分别为63.79%和39.39%。两种菌株均无溶血性且对抗菌药物敏感。结论菌株1-6与菌株S1具有抗氧化潜力且安全性高,可作为健康食品市场应用的高价值候选菌株。

淀粉型甘薯RS3制备工艺及体外抗消化特性

以淀粉型甘薯为原料,利用单因素试验研究不同淀粉乳质量浓度、pH值、压热温度、压热时间及冷却回生时间对甘薯三型抗性淀粉(resistant starch type 3,RS3)得率的影响,并通过响应面设计优化制备工艺。结果显示,响应面试验得出的最优制备条件为淀粉乳浓度13%、pH5.5、压热温度110℃、压热时间35 min,此时RS3得率为37.94%,与预测值仅相差0.92%,响应面模型与实际情况拟合良好。甘薯抗性淀粉RS3的体外抗消化特性研究表明,RS3的酶解率和模拟消化道的消化率低,展示很强的抗酶解、抗消化特性。电镜结果显示,RS3颗粒呈不规则块状,表面凹凸不平;结晶型以B型为主,颗粒有序度降低,双螺旋程度和结晶度提高,与原淀粉相比结构更加紧密,这些结构特性可以解释甘薯RS3的抗消化特性。