Preparation, characterization and the stability of ferrous glycinate nanoliposomes

Ferrous glycinate nanoliposomes prepared by the reverse-phase evaporation method (REV) from egg phosphatidylcholine (EPC) were investigated, based on the encapsulation efficiency, transmission electron microscopy (TEM), size distribution, and zeta potential. The nanoliposomes had high encapsulation efficiency, and TEM photomicrographs of nanoliposomes clearly showed their spherical shape. The size distribution and zeta potential indicated the stability of the nanoliposome suspensions. Retention ratio and size distribution of ferrous glycinate nanoliposomes were used to determine the influence of storage period, sonication and boiling water on the stability of ferrous glycinate nanoliposomes. Furthermore, in vitro stability of ferrous glycinate nanoliposomes in simulated gastrointestinal juice was evaluated. The nanoliposomes showed an acceptable stability in simulated gastrointestinal juice at 37 °C for 5 h. According to the results, ferrous glycinate nanoliposomes may be fit for the oral administration of ferrous glycinate and be used for the fortification of foodstuffs.     

Accelerated ripening of cheese using liposome-encapsulated enzyme

Improved efficiency of liposome encapsulation of a cheese-ripening enzyme and increased retention of encapsulated enzyme by cheese curd are reported. The economy of enzyme usage for accelerating the rate of ripening of Cheddar cheese has been improved about 100-fold over previously reported methods. This has made feasible the use of microencapsulated enzymes for large-scale cheese production. Objective measurement of cheese ripening by proteolytic indices, and subjective evaluation of flavour quality and intensity by trained taste panels, indicate that cheeses are ripened by the microencapsulated enzyme in half the normal time. Investigations aimed at further improving the efficiency and commercial feasibility of the process are reported, and the possibility of using this technology for other aspects of food processing are discussed.     

甘氨酸螯合铁纳米脂质体对铁强化牛奶氧化稳定性和感官质量的影响

研究了以甘氨酸螯合铁纳米脂质体作为铁强化剂对牛奶氧化稳定性和感官质量的影响。通过反相蒸发法以蛋黄卵磷脂为主要壁材制备出了具有良好球形结构和均匀粒径分布的甘氨酸螯合铁纳米脂质体,将其加入牛奶中进行铁强化。分别用硫代巴比妥酸法、色差分析、粘度测定和浊度测定对牛奶铁强化前后及其贮藏期间的氧化稳定性和感官质量进行评价。结果表明:与以硫酸亚铁和甘氨酸螯合铁作为铁强化剂相比,以甘氨酸螯合铁纳米脂质体为铁强化剂的强化奶的脂质氧化程度更低,组织状态更稳定。     

Encapsulation of Food Ingredients Using Nanoliposome Technology

Nanoliposomes are microscopic vesicles composed of phospholipid bilayers entrapping one or more aqueous compartments. Their unique properties have triggered numerous applications in several scientific and technological fields. Nanoliposomes can provide controlled release of various bioactive agents, including food ingredients and nutraceuticals, at the right place and the right time. Therefore, they increase the effectiveness and cellular uptake of the encapsulated material. Reactive, sensitive, or volatile additives (vitamins, enzymes, antioxidants, slimming agents, etc.) can be turned into stable ingredients using nanoliposomes. This article reviews various aspects of nanoliposomes including currently available preparation methods, and their application in food technology.     

Application of Liposomes in Some Dairy Products

The application of liposomes as potential carriers to deliver food components is considerably an innovative technology. While the application of liposome technology has been very limited to date, researches indicating the potential of liposomes for improving the flavor of ripened cheese using accelerated methods, the targeted delivery of functional food ingredients, the synergistic delivery of ascorbic acid and tocopherols for promoting antioxidant activity in foods, and the stabilization of minerals (such as iron) in milk have been performed. In the food industry, liposomes and nanoliposomes have been employed to encapsulate flavoring and nutritive agents, and also, they have been suitable candidates to deliver antimicrobials. In this paper, application of lipase, proteinase, nisin, and flavor-containing liposomes in products during the processing (such as cheese maturity) as well as the application of liposomes-encapsulated micronutrients (such as iron) in milk are reviewed.     

叶黄素纳米脂质体的多聚赖氨酸修饰及其体外释放性能

采用亲水性阳离子多肽多聚赖氨酸(ε-poly-L-lysine,ε-PLL)通过静电吸附作用修饰叶黄素纳米脂质体(LUT-NLP),构建新型ε-PLL修饰纳米脂质体载运体系,提高对脂溶性叶黄素的包封和释放性能。采用反向溶剂法制备LUT-NLP,通过单因素试验和正交试验优化ε-PLL修饰LUT-NLP的工艺条件,并考察修饰前后LUT-NLP的结构特征和体外释放性能。结果表明:在ε-PLL用量0.08%、pH 6.0、修饰时间2.0 h时,叶黄素的包封率可达95.36%;动态光散射分析表明修饰后的脂质体平均粒径为(299.4±8.4) nm,多分散指数(PDI)降低(<0.3),膜电位升高;透射电子显微镜结果显示由于静电吸附作用,ε-PLL与脂质体表面结合形成保护包覆结构;体外释放性能评价结果显示,经ε-PLL修饰的LUT-NLP在胃肠液环境中对叶黄素的释放率显著升高。ε-PLL修饰可改善脂质体结构,增强对脂溶性叶黄素的包封效果和胃肠消化释放性能。     

EXOGENOUS ENZYMES IN DAIRY TECHNOLOGY — A REVIEW1

A substantial number of enzymes have potential applications in dairy technology but most are not commercially viable, at least at present. In this review, the principal applications of proteinases (rennets for cheese manufacture, acceleration of cheese ripening, modification of the functional properties of milk proteins, preparation of nutritionally and physiologically active peptides), lipases (mainly in cheese ripening) and lysozyme are discussed.     

Liposomes as Proteinase Carriers for the Accelerated Ripening of Saint-Paulin Type Cheese

The possibility of accelerated cheese ripening through addition of liposome entrapped proteinase to milk was investigated. Both enzyme encapsulation rate in liposomes and their retention in cheese were evaluated with multilamellar vesicles (MLV) and reverse-phase evaporation vesicles (REV). Using REV in Saint-Paulin type curd, no nitrogen loss was observed to the whey due to the added enzymes in liposomes. In cheese, REV produced a more progressive proteolysis during ripening than MLV did. REV addition did not lead to texture defects. Bitterness development, a critical defect in enzyme added cheese, could be delayed and minimized using REV.     

Fatty acid profiling of bovine milk and cheese from six European areas by GC‐FID and GC‐MS

The fatty acid (FA) composition of milk from six European areas, as well as the alteration in the FA profile during cheese production, was studied using both a targeted GC‐FID and an untargeted GC‐MS approach. By applying principal component, partial least square discriminant and chemical similarity enrichment analysis, a discrimination of the geographical areas could be achieved highlighting important FA classes such as odd‐ and branched‐chain FAs for the differentiation. The FA profile remained constant during cheese production, and aroma compounds have been identified as biomarkers for the ripening methods used, namely foil and smear ripening.     

Physicochemical and microbial properties of nanopowdered peanut sprout‐supplemented Caciocavallo‐like cheese during ripening

This study was carried out to investigate the physicochemical and microbial properties of nanopowdered peanut sprout‐supplemented Caciocavallo‐like cheese (NPSCC) during ripening at 14 °C for 6 weeks. The total phenol contents and lactic acid bacteria counts in NPSCC were significantly higher than those in the control, indicating that nanopowdered peanut sprout could potentially be used as a prebiotic and potential source of dietary antioxidants in the dairy products. Thiobarbituric acid values of the cheese were significantly decreased and the production of short‐chain free fatty was not significantly different when nanopowdered peanut sprout was added into the production of Caciocavallo‐like cheese.     

Influence of adjuncts as a debittering aids in encountering the bitterness developed in cheese slurry during accelerated ripening

An attempt was made to accelerate the flavour development in cheese base with the help of exogenous proteolytic and lipolytic enzymes (1:1 proportion, each at the rate of 0.025% by weight of cheese‐base) and ripening at elevated temperatures (i.e. 20 ± 1 °C) for up to 12 days. To counter the bitterness developed, adjunct cultures were used: viable or attenuated (freeze‐shocked or heat shocked). Study of biochemical characteristics, electrophoretic pattern and sensory evaluation of the product were carried out. An acceptable enzyme‐modified, lightly salted cheese base was obtained using 0.025% each of proteolytic and lipolytic enzymes, along with 5% starter culture and adjuncts followed by ripening up to 12 days. Freeze‐shocked adjunct Lactobacillus helveticus produced enzyme‐modified cheese base with no detectable bitterness. The usage of exogenous enzymes, temperature of ripening, ripening period and interactions amongst these parameters had significant (P < 0.01) influence on all of the biochemical characteristics monitored.     

Effect of nanoliposomal entrapment on antioxidative hydrolysates from goose blood protein

In this study, the encapsulation of goose blood hydrolysate (GBH) was performed within nanoliposomes. We investigated the physicochemical properties, stability, antioxidant indices, the morphology of nanoparticles, the digestion stability in simulated gastrointestinal fluid, differential scanning calorimetry (DSC) analysis, and Fourier transform infrared (FTIR) spectroscopy. GBH was successfully encapsulated into nanoliposomes using reverse-phase evaporation method. The entrapment efficiency of GBH-loaded nanoliposomes was about 70.99 ± 2.85%, the average particle size was 93.3 ± 2.45 nm, the zeta-potential of GBH-loaded nanoliposomes was −30 mV, and the morphology of GBH-loaded nanoliposomes was characterized by transmission electron microscope. Moreover, the results of DSC and FTIR showed that the GBH nanoliposome was more stable than the empty liposomes due to hydrogen bond complexation between liposome and GBH. The release of GBH from nanoliposomes could be significantly controlled, and the release ratios were 48.9 ± 2.96% in simulated gastric fluid and 59.9 ± 5.30% in simulated intestinal fluid, respectively, proving that degradation rate of antioxidant activities of GBH encapsulated in nanoliposomes was decreased. In conclusion, nanoliposomes embedding is a promising and effective way to increase the stability of hydrolysates from GBH and produce various types of functional food.     

Comparative physicochemical stability and efficacy study of lipoid S75-biopeptides nanoliposome composite produced by conventional and direct heating methods

Liposomes are used as effective nanodelivery devices to improve the physicochemical stability and biological efficacy of the encapsulated peptides and proteins. In this study, nanoliposome composite of lipoid S75-entrapped angiotensin I-converting enzyme (ACE)-inhibitory biopeptides was prepared by conventional (BLS75-CM) and direct heating (BLS75-DHM) methods. The nanoliposomes (BLS75-CM and BLS75-DHM) were stored at 4^°C for 8 weeks and evaluated for physicochemical stability in terms of particle size, polydispersity index (pdi), zeta potential, and encapsulation efficiency (EE). These were also studied for residual ACE-inhibitory efficacy following their digestion under simulated gastrointestinal tract condition. The BLS75-CM was found to maintain higher physicochemical stability in terms of particle size, pdi, and zeta potential compared to BLS75-DHM. However, the BLS75-DHM indicated higher EE and efficacy with greater residual ACE-inhibitory activity of 47.37% compared to 44.18% and 36.84% that were obtained for the digested BLS75-CM and digested biopeptides without encapsulation, respectively. In vitro release study showed a cumulative biopeptides release of 66.41% and 69.00% from BLS75-CM and BLS75-DHM, respectively. The results of transmission electron microscopy showed spherical appearance of the nanoliposome capsules while Fourier Transform Infrared spectroscopy indicated the presence of ionic complexation and hydrogen bonds between the biopeptides and their phospholipid matrix.     

修饰发酵剂细胞促熟干酪的研究进展

修饰发酵剂细胞是采用各种物理、化学或基因修饰等方法使发酵剂(主要是乳酸菌)不能生长而不致产生过量的乳酸。同时在干酪中添加时细胞会完整存在，并能在成熟期间释放出活性胞内酶。修饰发酵剂的方法主要有热休克、冷休克、冷冻或喷雾干燥、溶菌酶处理、溶剂处理和基因修饰等。这些方法修饰乳酸菌(包括乳球菌，乳杆菌)与原发酵剂一并加入乳中，可加速干酪中的蛋白质降解和脂肪分解，缩短其成熟期，且增强风味(减少苦味)，在促熟干酪方面取得了较好的实验效果。综述了现有的修饰发酵剂细胞促熟干酪的方法，详述了热休克、冷休克这两种常用的方法，最后对修饰发酵剂细胞促熟干酪的应用前景作以展望。     

Nanoliposomal encapsulation of chia oil for sustained delivery of α-linolenic acid

Chia oil is a popular source of ω-3 fatty acids, typically α-linolenic acid. This study reports the encapsulation of chia oil in nanoliposome to protect ω-3 fatty acids and to obtain a sustained release of chia oil during digestion. Nanoliposomal encapsulation was carried out using solvent evaporation, followed by sonication. The encapsulation process was conducted using different lipid contents, with different concentrations of soy phosphatidylcholine (S), Tween 80 (T) and volumes of the aqueous phase. The maximum encapsulation efficiency was found to be 88.31%, and the average particle size was 49.25 nm; a moderate repulsion among the particles was observed. Differential scanning calorimetry study revealed enhanced thermal stability of chia oil in nanoliposomes. A negligible release (3.39%) of encapsulated chia oil was observed in the simulated gastric fluid, and a 74.72% sustained release was recorded in the simulated intestinal fluid. This formulation can be a suitable supplement of ω-3 fatty acids for food and therapeutic applications.     

干酪中的生物活性物质及其作用

干酪是牛奶凝乳后新鲜或成熟的产品,易消化且富含多种营养成分,是蛋白质、短链脂肪酸、维生素和矿物质的优质来源。除 了释放抗氧化和抗菌等功能性多肽,同时也释放一些抗炎、抗癌等功能性脂类,如共轭亚油酸,还可以释放γ-氨基丁酸（GABA）,它 参与生理功能,如神经传递等。 该文主要介绍干酪在成熟过程中释放的生物活性物质及其作用。     

Mechanisms of incorporation and release of enzymes into cheese during ripening

The enzymes involved in cheese ripening and the factors affecting their activity in cheese is reviewed. The review begins by outlining the various enzymes that contribute to cheese ripening including those originating from milk, coagulant, starter and non-starter Lactic Acid Bacteria, and those added as exogenous preparations to accelerate flavour development. Factors influencing the retention, release and residual activity of these enzymes in cheese are discussed along with an outline of innovative methods to enhance the retention and release of exogenous enzymes.     

Disruption treatments on two strains of Streptococcus thermophilus: Levels of lysis/permeabilisation of the cultures,and influence of treated cultures on the ripening profiles of Cremoso cheese

The influence of several disruption treatments on the viability and the release of intracellular enzymes of two strains of Streptococcus thermophilus (St1 and St2) was studied. In addition, the impact of the incorporation of disrupted cultures of St2 in Cremoso cheese was investigated. Enzymatic (mutanolysin) and mechanical treatments (bead mill and ultrasound) were the most effective for lysis, while chemical methods (ethanol and SDS) were effective as permeabilising agents. Physical methods (freeze and heat shock) were not suitable for disruption. The application of disrupted cultures of St2 in Cremoso cheese led to slight changes on the ripening profiles: decrease in lactose level, and increase in total free amino acids and acetic acid. This work demonstrated that certain types of disrupted St2 cultures could be suitable as source of key enzymes for the production of food with improved properties, such as lactose-hydrolysed dairy products or cheeses with higher proteolysis.     

Flavor of Cheddar Cheese: A Chemical and Sensory Perspective

Considerable knowledge has been accumulated on the biochemical processes occurring during ripening of Cheddar cheese, which in turn has major consequences on flavor and texture development. The present review outlines major metabolic pathways and agents involved in the modification of milk constituents in Cheddar cheese ripening. Mechanisms of volatile flavor and off‐flavor production and recent developments in the analysis, both sensory and instrumental, of Cheddar flavor and flavor compounds are also detailed here.     

生物技术在干酪加工中的应用

综述了生物技术在原料乳品质改进、凝乳酶、干酪发酵剂、干酪促熟、干酪包装及乳清处理等不同干酪加工环节中的应用.