Original article: In vitro starch digestion and potassium release in sweet potato from Papua New Guinea†

Twenty samples of sweet potato from Papua New Guinea, made up of cultivars 3‐mun, Carot kaukau, Wahgi besta, Nillgai, Baiyer kaukau, and 1‐mun from three provinces, three farmers, and three locations, were subjected to an in vitro starch digestion procedure. Digestion of starch was studied by glucometry, while potassium release was monitored using electrochemistry. The potassium content of the nondigested samples ranged from 4 to 17 mg g^?1 dry solids, while the starch content was from 47 to 80 g per 100 g dry solids and independent of G × E effects. In vitro starch digestibility (2–75 g digested starch per 100 g dry starch) significantly (P < 0.05) varied with time in a nonlinear manner with biphasic digestograms. Potassium release was independent of time in in vitro gastric and pancreatic regions, but more potassium was released during pancreatic than gastric digestion. Results suggest differences in resistant starch and bioavailability of (micro)nutrients that could influence utilisation of sweet potato.     

大米主食制品中污染物镉的体外消化释放研究

对含污染物镉的大米主食样品米饭和米线进行体外模拟消化,采用石墨炉原子吸收分光光度法(GF-AAS)对样品中镉进行定量检测。口腔阶段镉释放率:生大米原料粉(34.85%)米线(5.69%)米饭(0%);胃阶段释放率:米饭(74.51%)米线(71.62%)生大米原料粉(0%);小肠阶段中的最大释放率为:4 h时生大米原料粉(60.19%)7 h时米线(45.35%)5 h时米饭(37.06%)。结果表明:不同大米主食样品在不同消化阶段中污染物镉的消化释放有显著差异,已消化释放出的镉在不同时间和消化部位还会被重新吸附结合,使镉释放率增加又降低;在小肠1~3 h消化时间下,米饭中镉消化释放率显著大于米线样品,而小肠消化3h后,则相反。该研究结果可作为大米及制品中污染物镉生物可给性的研究基础,为进一步合理食用和风险暴露评估提供参考。     

乙基纤维素对油脂中维生素A体外消化释放速率的影响

以乙基纤维素EC100作为油脂质构剂添加到起酥油样品中,研究其控制性释放脂溶性维生素A的特性。体外模拟消化试验表明EC100具有显著的缓释作用,随着EC100质量分数的增加(0%~6%),起酥油样品消化2 h时VA的累积释放率由20.52%降低至3.62%。Ritger-Peppas方程式拟合得到维生素A溶出参数n为0.45~0.89,显示VA的释放速率受化合物自身扩散和骨架溶蚀双重控制。扩散系数的测定结果验证了VA的浓度梯度是扩散的驱动力,且随着油脂中EC100质量分数的增加(0%~6%),VA在有机凝胶剂中的扩散系数呈降低趋势;侵蚀试验结果表明,当贮藏时间越长、贮藏温度越低及EC100添加量越大时,有机凝胶剂样品的侵蚀常数降低,并且添加乳化剂分子蒸馏单甘酯(DMG)的有机凝胶样品受侵蚀的程度较小。     

NSP酶对大麦体外消化的影响

大麦体外消化试验结果揭示，添加NSP酶（GXC）使大麦中干物质、粗蛋白、粗灰分、无氮浸出物、粗脂肪和粗纤维的消化率分别提高了18．13％、20．27％、15．99％、16．42％、和26．93％和30．02％；大麦中各种氨基酸体外消化率显著提高，幅度为11．83％－61．39％；添加NSP酶使大麦胚乳细胞壁在体外完全降解；消化过滤液中葡萄糖和总氨基酸含量分别提高了17．58％和10．26％；而粘度降低了4．51％。     

菊糖对马铃薯淀粉糊流变特性及体外消化的影响

为了研究菊糖对马铃薯淀粉糊流变特性及体外消化的影响,以马铃薯淀粉为原料,通过流变仪测试和体外酶解等方法测定菊糖-马铃薯淀粉共混体系的特性变化。流变仪测试结果表明:在试验的菊糖添加量范围内,菊糖-马铃薯淀粉共混糊的流变学特性均符合幂率模型,为假塑性流体;菊糖的添加在一定程度上降低了淀粉糊黏度,且随着添加量的增加,这一趋势加大。体外酶解结果表明:菊糖可以在一定程度上抑制马铃薯淀粉的水解速度及程度,且随着菊糖添加量的增加其抑制程度也相应增加;水解指数HI及预测血糖值e GI均随着菊糖添加量的增加而逐渐降低;在菊糖最大添加量时(菊糖与淀粉配比为1∶5),菊糖-淀粉共混体系的水解率、HI和e GI值分别由原淀粉的70%、57.87和71.48降至50%、42.74和63.17。研究结果提示适量的菊糖不仅可以改善马铃薯淀粉糊的流变性能,还可以降低其血糖指数。     

Stability and antioxidant activity of phenolic compounds during in vitro digestion

The impact of phenolic compounds on the human body depended on the type, content, bioavailability, and antioxidant activity. After digestion, different phenolic compounds had different changes of bioavailability and antioxidant activity, which needed to be considered in the application. In this experiment, the structural stability and antioxidant activity of 27 phenolic compounds (phenolic acids, flavonols, flavonoids, and flavanones) were investigated during the in vitro simulated digestion. This experiment eliminated the influence of food matrix, provide a basis for regularity for the changes of phenolic substances in different materials. Results showed that the bioaccessibility of phenolic compounds with different structures varied, and there was a conformational relationship between the structure and stability. After oral digestion, most of the phenolic compounds underwent degradation and the cellular antioxidant activity (CAA) values decreased to a large extent (p < 0.05). After gastric digestion, the content (p > 0.05) and CAA values (p < 0.05) of most phenolic compounds increased. However, after intestinal digestion, the phenolic compounds were degraded to a greater extent, and different structures of phenolic compounds had different changes in CAA values (p < 0.05). In general, the CAA values of most phenolic compounds after in vitro digestion were lower than the initial value. The 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2′-azino-bis (3-ehylbenzthiazoline-6-sulfonic acid) (ABTS), and ferric reducing antioxidant power (FRAP) values of phenolic acids and flavonols decreased after in vitro simulated digestion (p < 0.05), while the values of DPPH, ABTS, and FRAP of most flavonoids (p < 0.05) increased. The increased oxygen radical absorption capacity (ORAC) values were found in most phenolic acids, flavonols, and flavonoids (p < 0.05), and most flavanones showed unremarkable changes in ORAC values (p > 0.05). In general, the changing trend of chemical-based antioxidant activity was consistent with the content of phenolic compounds.     

压力烹调对五种食材中淀粉消化性的影响

目的:探讨不同烹调方法对红小豆、莲子、山药片、芡实、薏米5种富含淀粉的保健食材的碳水化合物消化特性的影响,为科学食用传统食材提供依据。方法:体外模拟消化方法测定各时间点的水解率、快消化淀粉、慢消化淀粉和抗性淀粉等指标。结果:压力烹调显著影响样品的水解速率和淀粉类型,水解指数增大,快消化淀粉含量增加,抗性淀粉含量减少。但所有样品的预期血糖负荷均显著低于粳米样品。红小豆和莲子经过压力烹调仍保持低消化速度和低EGL特性。结论:压力烹调对提高难烹煮碳水化合物消化率有利,需要控制血糖的人可以通过选择慢消化食材和烹调参数来控制淀粉类型和EGL的变化。     

体外模拟消化对四种杂粮中酚类物质及其降脂活性的影响

杂粮中富含具有生理活性的多酚类化合物。本实验研究了4种常见杂粮(薏米、荞麦、青稞、红豆)在体外模拟消化过程中酚类物质的变化以及其降脂活性。结果表明,经模拟体外消化后荞麦具有最高的总酚含量(27.78±0.14)mg GAE/100 g及黄酮增长率57.9%。并利用油酸诱导HepG2细胞建立高脂模型,测定以2.5 mg/mL为上样浓度的4种杂粮多酚提取物干预前后细胞内TG及LDL-c含量的变化。结果表明荞麦多酚表现出了最佳的生物利用度及降脂活性,其干预组与模型组相比甘油三酯浓度下降了1/3,达到(0.156±0.032) mmol/g prot,低密度脂蛋白降至(0.025±0.005) mmol/g prot,表现出最佳的降脂活性,为进一步研究其作用机理以及降脂相关的功能食品及保健品的开发提供参考。     

Berry fruits-enriched pasta: effect of processing and in vitro digestion on phenolics and its antioxidant activity,bioaccessibility and potential bioavailability

Pasta samples were made by substituting wheat flour (2.5% and 7.5%) for lyophilised raspberry, boysenberry, and redcurrant and blackcurrant. Total polyphenol content showed minimum variation during processing while anthocyanins presented high degradation. In general, the first minutes of cooking showed the major detrimental effect on antioxidant activity. In vitro starch hydrolysis showed the lowest value with the addition of raspberries and boysenberries. During simulated digestion, polyphenols were released from pasta matrix reaching a 2.3- to 4.3-fold increase in bioaccessible polyphenols. Likewise, values observed for reducing power and free radical scavenging activity ranged from a 0.7- to 2.0-fold and 1.6- to 6.8-fold increase in relation to cooked pasta, respectively. In addition, ≈40% of dialysability was observed for scavenging activity. In conclusion, enrichment of pasta with fine fruits is an effective tool to obtain a product with enhanced antioxidant potential.     

体外模拟消化技术研究进展

依据体外消化状态和消化部位的不同对体外模拟消化进行了分类、简述,对不同种类的体外模拟消化试验进行了总结分析,并列举了体外模拟消化在不同营养成分中的应用情况.     

sInfluence of starch and protein molecular interactions on the in vitro digestion characteristics of biscuits partially substituted with pulse flours

Recent research has shown that pulse-derived ingredients present a technological alternative to cereals, higher protein and fibre content, and differentiated starch characteristics. In this work, the partial substitution of pulse flours with and without heat moisture treatment (HMT) was evaluated in a biscuit model. The digestion residues at 20 and 120 min that correspond to rapidly, slowly and resistant starch from the Englyst methodology were analysed by DSC, X-Ray and ATR-FTIR. The use of pulse flours in biscuits improved their thermal stability (ΔH = 3.01 and 4.99 J/g for control and Lentil + HMT), preserving a fraction of particularly ling glucans, that influenced the decreasing in the rapidly available starch from 55.26 to 24.11 % (Control and Faba bean + HMT), and enhanced its protein's digestibility from 75.26 to 87.43 % for the same sources. Among pulses, there were similarities regarding their resistance to enzymatic hydrolysis that may help select those with better organoleptic attributes.     

Synthesis and in vitro digestion of resistant starch type III from enzymatically hydrolysed cassava starch

Resistant starch type III (RS III) was synthesised from cassava starch by autoclaving followed by debranching with pullulanase, at varied concentrations (0.4–12 U g^?1) and times (2–8 h), and recrystallisation (?18 to 90 °C for 1–16 h). The highest RS III yield (22 g/100 g) was obtained at an enzyme concentration of 4 U g^?1 after 8 h incubation, followed by recrystallisation at 25 °C for 16 h. Varying the recrystallisation conditions indicated that higher RS III yields (30–35 g/100 g) could be obtained at 90 °C within 2 h. Thinning cassava starch using α‐amylase prior to debranching using pullulanase did not further increase the RS III content. In vitro digestion data showed that whereas 44% RS III was digested after 6 h, the corresponding value for cassava starch was 89%.     

膳食纤维对饼干体外消化速率的抑制作用

本研究以马铃薯全粉/籼米粉混合物(3:2)制作饼干(P1)作为对照,分别将燕麦麸(28%)、菊粉(22%)、燕麦麸/菊粉(28%/22%)添加至马铃薯全粉/籼米粉混合物(3:2)中制成饼干P2,P3和P4。通过测定淀粉糊化特性、淀粉水解率、葡萄糖释放量、蛋白质水解率及氨基酸含量等指标,采用体外模拟胃肠消化方法考察燕麦麸、菊粉对不同配方饼干中淀粉和蛋白质消化特性的影响。结果表明,添加燕麦麸、菊粉可降低饼干中淀粉的糊化度,淀粉糊化度从低到高依次为P4(33.41%),P2(38.23%),P3(38.35%),P1(53.79%)。燕麦麸和菊粉能延缓淀粉水解产生葡萄糖,葡萄糖释放量从低到高依次为P3(101.56μg/m L),P4(102.29μg/m L),P2(108.63μg/m L),P1(125.46μg/m L),菊粉对饼干中淀粉代谢的影响大于燕麦麸。饼干P1淀粉含量最高(78.35%),累积葡萄糖释放量最高(125.46μg/m L),淀粉水解率最低(31.92%)。燕麦麸和菊粉能抑制蛋白质水解率,胃部蛋白质水解率从低到高依次为P2(53.79%)、P4(64.86%)、P3(74.28%)、P1(83.24%),燕麦麸对饼干中蛋白代谢的影响大于菊粉。由此可见,添加燕麦麸、菊粉可在一定程度上抑制饼干的体外消化速率。     

抗性淀粉体外消化模拟的研究

采用体外消化模拟方法,研究了抗性淀粉在人工胃肠液和大肠液中的消化吸收情况,并用原淀粉作为对照组。结果表明,抗性淀粉和原淀粉在生理盐水中均没有被分解,生理盐水对抗性淀粉的消化毫无影响。与对照组原淀粉相比,抗性淀粉在人工胃液(pH3、pH4、pH5)和人工肠液(pH6.8)中变化很小,人工胃液和人工肠液对抗性淀粉不起消化作用。抗性淀粉在大肠液中有明显的失重,说明大肠液对抗性淀粉有影响,抗性淀粉能够被大肠中的微生物发酵或部分发酵。从而说明抗性淀粉不能在胃和小肠中消化吸收。     

不同链长单甘酯-籼米淀粉复合物结构及体外消化特性

研究不同链长脂肪酸单甘酯添加量变化时,单甘酯-籼米淀粉复合指数和糊化性质双变量相关性,通过傅里叶变换红外光谱仪、差示扫描量热仪、X-射线衍射分析仪和扫描电镜,研究单甘酯链长、添加量及温度对籼米淀粉-单甘酯复合物结构和体外消化特性的影响。研究结果表明:单甘酯碳链越长,与籼米淀粉的复合程度越高,且越易在冷却过程中形成黏度峰。相比于月桂酸单甘酯和硬脂酸单甘酯,棕榈酸单甘酯与籼米淀粉形成的复合物具有更高的焓变值、结晶度。硬脂酸单甘酯-籼米淀粉复合指数和糊化特性显著相关(除最低黏度值外);不同链长脂肪酸单甘酯-籼米淀粉复合指数与快消化淀粉含量显著负相关。     

Effects of simulated gastric and intestinal digestion on chitooligosaccharides in two in vitro models

Chitooligosaccharides (COS) with different degree of polymerisation (DP) have different physiological activities such as anti-tumour and anti-hyperlipidemia activities. However, the digestive process might lead to the change of DP of COS as well as cause the change of physiological activities in vivo. In this study, two in vitro digestion models (static and dynamic) were used to investigate digestion behaviours of COS and the influencing factors during digestion with or without food matrix. The results showed that COS with DP 2–5 were indigestible and COS with DP 6–10 degraded with time during gastric and intestinal digestion. Pepsin, pancreatin and lipase were the main factors leading to degradation. Food matrix could protect COS with DP 6–10 from degradation during gastric digestion. However, the degradation of COS with DP 6–10 accelerated and the degradation of COS with DP 5 occurred during intestinal digestion with food matrix due to pancreatin, lipase and bile salt.     

体内外消化高直链抗性水稻淀粉的波谱特性

以基因工程培育出来的高直链抗性淀粉水稻(TRS)为材料,利用粉末X射线衍射、傅里叶变换红外光谱分析技术,研究体内外消化TRS淀粉的波谱特性。结果表明：不被消化的抗性淀粉直链淀粉含量显著升高;TRS淀粉为C型晶体淀粉,由A型和B型晶体淀粉组成,其中A型晶体比B型晶体消化降解快,B型晶体具有抗消化降解的作用;TRS淀粉的无定形区域易被消化降解。     

脂质体在体外消化过程中的氧化稳定性

分别建立成人和婴儿体外胃、肠单独消化模型以及胃肠连续消化模型,通过检测脂质过氧化物值(POV)和硫代巴比妥酸(TBARS)反应物浓度,研究脂质体在模拟消化过程中的氧化稳定性。结果表明,脂质体在模拟人体单独胃消化过程中结构保持稳定,而在模拟小肠环境易受胰酶和胆盐的作用发生氧化,并且在模拟胃中和模拟肠中婴儿的POV和TBARS值均显著低于成人(p<0.05);在连续消化过程中,模拟婴儿胃部消化时间对其继续在小肠消化的氧化程度影响较小(p>0.05),而模拟成人胃肠连续消化产生的过氧化物量相对较多,脂质体氧化程度比较高,结构破坏较严重。      

食物成分消化模型的研究进展

体外消化模型即在生物体外以合适的条件模拟人体胃肠道的消化环境,可以用来预测食物的可消化性、食物成分的释放、结构的变化等。体外消化模型是基于体内消化情况而建立的,两者之间有一定的相关性,能从一定程度上反映摄入物质的消化利用情况,又具有简便易行的特点,因而在食品营养吸收、药物代谢、有效成分生物利用、食品摄入安全评价等方面的应用越来越受到重视。本文系统地介绍了近十年来蛋白质、碳水化合物、脂质以及维生素等食物成分的体外消化模型及其建立的关键因素,如酶浓度、pH、消化时间、颗粒大小等,对已报道的体外消化模型进行了总结,以期对食物成分体外消化模型的建立和发展有所帮助。