基于食品液态体系的功能因子靶向传输系统的构建及其释放研究

功能因子的储藏稳定性和控制释放是通过一定的微囊化控释传输系统来实现的。本研究采用挤出滚圆和流化床薄膜包衣技术,构建了基于液态食品体系的醋酸酯抗消化淀粉薄膜包衣微丸传输系统,分别考察了不同厚度的醋酸酯淀粉薄膜包衣微丸在酸奶中储藏过程及体外模拟人体消化道运转过程中功能因子的释放规律及微丸表面包衣膜层的微观形貌变化。研究表明,在相同的储藏时间下,包衣厚度越大,微丸表面包衣膜层越完好,越能有效阻止功能因子的释放;当醋酸酯抗消化淀粉包衣增重达到9.94%时,其中的功能因子在储藏22d不释放;同时,在酸奶中储藏不同时间后,不同包衣厚度的微丸在模拟消化道中运转时的表面形貌变化与其释放情况相符。研究为筛选适合液态食品体系的功能因子控释传输载体材料及控释传输系统的构建奠定了基础。     

A Comparative Study of Natural Antimicrobial Delivery Systems for Microbial Safety and Quality of Fresh‐Cut Lettuce

Nanoencapsulation can provide a means to effectively deliver antimicrobial compounds and enhance the safety of fresh produce. However, to date there are no studies which directly compares how different nanoencapsulation systems affect fresh produce safety and quality. This study compared the effects on quality and safety of fresh‐cut lettuce treated with free and nanoencapsulated natural antimicrobial, cinnamon bark extract (CBE). A challenge study compared antimicrobial efficacy of 3 different nanoencapsulated CBE systems. The most effective antimicrobial treatment against Listeria monocytogenes was chitosan‐co‐poly‐N‐isopropylacrylamide (chitosan‐PNIPAAM) encapsulated CBE, with a reduction on bacterial load up to 2 log₁₀ CFU/g (P < 0.05) compared to the other encapsulation systems when fresh‐cut lettuce was stored at 5 °C and 10 °C for 15 d. Subsequently, chitosan‐PNIPAAM‐CBE nanoparticles (20, 40, and 80 mg/mL) were compared to a control and free CBE (400, 800, and 1600 μg/mL) for its effects on fresh‐cut lettuce quality over 15 d at 5 °C. By the 10th day, the most effective antimicrobial concentration was 80 mg/mL for chitosan‐PNIPAAM‐CBE, up to 2 log₁₀ CFU/g reduction (P < 0.05), compared with the other treatments. There was no significant difference between control and treated samples up to day 10 for the quality attributes evaluated. Chitosan‐PNIPAAM‐CBE nanoparticles effectively inhibited spoilage microorganisms’ growth and extended fresh‐cut lettuce shelf‐life. Overall, nanoencapsulation provided a method to effectively deliver essential oil and enhanced produce safety, while creating little to no detrimental quality changes on the fresh‐cut lettuce.     

Influence of the Thermal Stabilization Process on the Volatile Profile of Canned Tomato‐Based Food

The literature contains several papers dealing with the volatile constituents contributing to the aroma of fresh and processed tomatoes. Along with the traditional tomato‐based products, tomato‐based pâtés, characterized by complex ingredient formulations, are commonly consumed as a seasoning for pasta, and as a dressing for meats, salads, and sandwiches. To the best of our knowledge, no investigations have been published on the influence of thermal stabilization treatments on the composition of volatile compounds in tomato‐based pâtés. To this aim, thermally stabilized and not stabilized tomato‐based pâtés were subjected to the analysis of volatile compounds. The results obtained highlighted the influence of the thermal stabilization process on the evolution of volatile composition tomato‐based pâtés. In particular, the terpenic compounds showed significant decreases after the thermal stabilization process treatment, due to their degradation and oxidation favored by high temperatures. The thermal stabilization caused, moreover, an increase in volatile compounds deriving from lipid oxidation and Maillard reaction, characterized by low‐sensory thresholds, and from the thermal degradation of carotenoids and fresh tomato‐derived compounds.     

食物活性成分结肠靶向输送系统研究进展

随着肠道菌群的发现及其健康促进功能的明确,使得结肠的营养及健康状况受到大量关注。以结肠靶向输送体系为载体经口服主动向结肠递送食物活性成分,能够达到优化肠道菌群和/或维护结肠健康的效果。因此,食物活性成分结肠靶向输送体系是结肠功能性食品研发或结肠营养支持的技术核心。在查阅近10年相关文献的基础上,本文着重对食物活性成分（益生菌、疏水小分子活性物质、亲水小分子活性物质和大分子活性物质）结肠靶向输送体系的构建原理（pH敏感型输送系统、时间依赖型输送系统、菌群/酶触发型输送系统和其他类型输送系统）及其应用现状进行综述,并就食物活性成分结肠靶向输送体系研究开发所存在的问题及其发展方向进行阐述。     

食品组份对风味释放与风味感觉的影响

本文主要就蛋白质、多糖、其它的非脂类化合物及脂类物质与风味化合物间的相互作用及其对风味释放与风味感觉的影响进行了较系统详细的综述。     

Effect of Type of Protein‐Based Microcapsules and Storage at Various Ambient Temperatures on the Survival and Heat Tolerance of Spray Dried Lactobacillus acidophilus

The aims of this study were to evaluate the effect of types of protein‐based microcapsules and storage at various ambient temperatures on the survival of Lactobacillus acidophilus during exposure to simulated gastrointestinal tract and on the change in thermo‐tolerance during heating treatment. The encapsulating materials were prepared using emulsions of protein (sodium caseinate, soy protein isolate, or pea protein), vegetable oil, and glucose, with maltodextrin was used as a wall material. The formulations were heated at 90 °C for 30 min to develop Maillard substances prior to being incorporated with L. acidophilus. The mixtures were then spray dried. The microspheres were stored at 25, 30, and 35 °C for 8 wk and examined every 4 wk. The addition of proteins as encapsulating materials demonstrated a significant protective effect (P < 0.05) as compared to the control sample. Sodium caseinate and soy protein isolate appeared more effective than pea protein in protecting the bacteria after spray drying and during the storage at different room temperatures. Storage at 35 °C resulted in a significant decrease in survival at end of storage period regardless the type of encapsulating materials. The addition of protein‐based materials also enhanced the survival of L. acidophilus during exposure to simulated gastrointestinal condition as compared to the control. After spray drying and after 0th wk storage, casein, soy protein isolate, and pea protein‐based formulations protected the bacteria during heat treatment. In fact, a significant decrease in thermal tolerance was inevitable after 2 wk of storage at 25 °C.     

Solid‐State Protein–Carbohydrate Interactions and Their Application in the Food Industry

The growing interest in food component interactions, especially the solid‐state protein–carbohydrate ones, has led to a growing body of knowledge on the effects of these interactions on the physical, chemical, and structural properties of compositionally complex food systems. The goal of the present review is to survey the critical mechanisms involved in protein–carbohydrate interactions as a key step toward the rational formulation and processing of protein‐ and carbohydrate‐rich foods to produce products with desirable properties without adverse reactions. The hypotheses proposed on the stabilizing effects of carbohydrates on proteins and the role of different types of sugars in the extent of these interactions are reviewed in this article. Another aspect of this review involves the successful drying of proteins by spray‐drying, freeze‐drying, and supercritical‐fluid‐drying using carbohydrates. Finally, applications of these interesting phenomena to produce important food products including milk powder, infant formulas, bakery products, and fruit and vegetable juice powders are investigated.     

A Survey of Commercially Available Isomaltooligosaccharide‐Based Food Ingredients

Isomaltooligosaccharides (IMOs) are included in many commercially available food products including protein/fiber bars, shakes, and other dietary supplements. Marketed as “high fiber,” “prebiotic soluble fiber,” and/or as a “low‐calorie, low glycemic sweetener,” IMO may be present in significant amounts, for example, more than 15 g/item or serving. Herein, high‐pressure anion exchange chromatography with pulsed amperometric detection and high‐pressure liquid chromatography with differential refractive index detection are used to compare 7 commercially available IMO‐containing bulk food ingredients. The ingredients are typical of those produced either (a) via bacterial fermentation (“fermented” IMO or MIMO) of sucrose in the presence of a maltose acceptor mediated by a glucosyltransferase enzyme (dextransucrase), or (b) via transglycosylation of hydrolyzed starch with α‐glucosidase (“industrial” IMO). Analysis of the results with respect to digestibility suggests that the potential glycemic impact of the ingredients and products containing “industrial” IMO may be inconsistent with the product labeling and/or certificates of analysis with respect to overall fiber content, prebiotic fiber content, and glycemic response and are thus inappropriate for diabetic patients and those on low‐carbohydrate (for example, ketogenic) diets.     

Water Holding as Determinant for the Elastically Stored Energy in Protein‐Based Gels

To evaluate the importance of the water holding capacity for the elastically stored energy of protein gels, a range of gels were created from proteins from different origin (plant: pea and soy proteins, and animal: whey, blood plasma, egg white proteins, and ovalbumin) varying in network morphology set by the protein concentration, pH, ionic strength, or the presence of specific ions. The results showed that the observed positive and linear relation between water holding (WH) and elastically stored energy (RE) is generic for globular protein gels studied. The slopes of this relation are comparable for all globular protein gels (except for soy protein gels) whereas the intercept is close to 0 for most of the systems except for ovalbumin and egg white gels. The slope and intercept obtained allows one to predict the impact of tuning WH, by gel morphology or network stiffness, on the mechanical deformation of the protein‐based gel. Addition of charged polysaccharides to a protein system leads to a deviation from the linear relation between WH and RE and this deviation coincides with a change in phase behavior.     

以多糖和蛋白质为基质利用静电纺丝技术构建生物活性物质递送体系的研究进展

食品在加工和储藏过程中会受到高温、离子强度、酸碱性等诸多因素的影响,导致其生物活性物质极其不稳定。同时,如果这些生物活性物质直接暴露于胃肠道环境中,其生物利用率迅速降低且容易被降解,这些不利因素极大地限制了生物活性物质在食品工业化生产中的应用。因此,如何有效地包埋生物活性物质成为研究的热点问题。静电纺丝技术是一种新兴的活性物质包埋技术,利用该技术制备的纳米纤维在食品工业中具有潜在的应用价值。本文主要综述了静电纺丝的原理、影响因素和类型,以天然多糖和蛋白质为基质通过静电纺丝制备生物活性物质递送体系(纳米纤维)的研究进展,纳米纤维的制备过程、影响因素及其改善方法,并展望了静电纺丝在食品科学领域中的应用前景。     

Microencapsulation of Bifidobacterium bifidum F‐35 in Whey Protein‐Based Microcapsules by Transglutaminase‐Induced Gelation

Abstract: Bifidobacterium bifidum F‐35 was microencapsulated into whey protein microcapsules (WPMs) by a transglutaminase (TGase)‐induced method after optimization of gelation conditions. The performance of these WPMs was compared with that produced by a spray drying method (WPMs‐A). WPMs produced by the TGase‐induced gelation method (WPMs‐B) had larger and denser structures in morphological examinations. Native gel and SDS‐PAGE analyses showed that most of the polymerization observed in WPMs‐B was due to stable covalent crosslinks catalyzed by TGase. The degradation properties of these WPMs were investigated in simulated gastric juice (SGJ) with or without pepsin. In the presence of pepsin, WPMs‐A degraded more quickly than did WPMs‐B. Finally, survival rates of the microencapsulated cells in both WPMs were significantly better than that of free cells and varied with the microencapsulation method. However, WPMs‐B produced by TGase‐induced gelation could provide better protection for microencapsulated cells in low pH conditions and during 1 mo of storage at 4 °C or at ambient temperature.     

TEMPO氧化魔芋葡甘露聚糖微球的制备及其在运载食品活性因子中的应用

以2,2,6,6-四甲基哌啶-1-氧自由基（2,2,6,6-tetramethyl-piperidine-1-oxyl,TEMPO）为催化剂,次氯酸钠为氧化剂,对魔芋甘露聚糖（konjac glucomannan,KGM）进行氧化,制备出氧化度为80%的TEMPO氧化魔芋多糖（TEMPOoxidizedkonjac glucomannan,OKGM）。用OKGM为原料、Fe3＋为交联剂借助双重乳液法制备微球。内油相中包覆β-胡萝卜素,多糖水相吸附花色苷,实现亲疏水活性因子的共装载。红外光谱显示出KGM上羟基成功氧化为羧基;MTT法验证了OKGM没有细胞毒性;采用单因素试验,确定制备微球的最佳工艺条件是OKGM质量分数10%、FeSO4·7H2O与OKGM质量比1∶5、交联时间30 min、交联温度35 ℃;通过动态光散射法发现微球粒径分布在20～40 μm之间,平均粒径为26.8 μm;通过扫描电子显微镜和原子力显微镜观察了微球的表面形貌;荧光共聚焦显微镜显示微球中能够同时分布着花色苷和β-胡萝卜素。结果表明OKGM微球在多种活性因子的共装载方面有良好的应用前景。     

High-Pressure Processing as Emergent Technology for the Extraction of Bioactive Ingredients From Plant Materials

High-pressure processing is a food processing technique that has shown great potentials in the food industry. Recently, it was developed to extract bioactive ingredients from plant materials, known as ultrahigh pressure extraction (UPE), taking advantages of time saving, higher extraction yields, fewer impurities in the extraction solution, minimal heat and can avoid thermal degradation on the activity and structure of bioactive components, and so on. This review provides an overview of the developments in the UPE of bioactive ingredients from plant material. Apart from a brief presentation of the theories of UPE and extraction equipment systems, the principal parameters that influence the extraction efficiency to be optimized in the UPE (e.g., solvent, pressure, temperature, extraction time, and the number of cycle) were discussed in detail, and finally the more recent applications of UPE for the extraction of active compounds from plant materials were summarized.     

Stability Analysis of Zinc Oxide‐Nanoencapsulated Conjugated Linoleic Acid and Gamma‐Linolenic Acid

ABSTRACT: Conjugated linoleic acid (CLA) and gamma‐linolenic acid (GLA) were encapsulated with hydrated zinc oxide nanoparticles in an effort to improve their time and thermal stability. Encapsulated and nonencapsulated CLA and GLA were stored at 20, 30, 40, and 50 °C for 49 d. At various time points, encapsulated CLA and GLA were extracted, methylated, and analyzed using GC‐FID. Both encapsulated CLA and control CLA were stable when stored at 20, 30, and 40 °C for up to 49 d. However, control CLA was 100% degraded after 28 d at 50 °C, whereas encapsulated CLA was stable at 50 °C for 49 d. Similarly, both encapsulated GLA and control GLA were stable when stored at 20 °C for 49 d, but nonencapsulated GLA was 92% degraded after 49 d at 30 °C; encapsulated GLA was stable at 30 °C. Therefore, nanoencapsulation improves the time and temperature stability of CLA and GLA.     

Graduate Student Literature Review: Potential uses of milk proteins as encapsulation walls for bioactive compounds

Milk proteins have received much awareness due to their bioactivity. However, their encapsulation functions have not attracted enough attention. Milk proteins as encapsulation walls can increase the bioavailability of bioactive compounds. As the benefits of bioactive compounds are critically determined by bioavailability, the effect of interactions between milk proteins and active substances is a critical topic. In the present review, we summarize the effects of milk proteins as encapsulation walls on the bioavailability of active substances with a special focus. The methods and mechanisms of interactions between milk proteins and active substances are also discussed. The evidence collected in the present review suggests that when active substances are encapsulated by milk proteins, the bioavailability of active substances can be significantly affected. This review also provides valuable guidelines for the use of milk protein-based microcarriers.