Development and characterization of composite edible films based on sodium alginate and pectin

The objective of this study was to characterize physical properties including thickness, colour, water vapour sorption kinetics and isotherms, water vapour permeability, tensile strength, elongation at break, and microstructure of composite films prepared by casting sodium alginate and low methoxy pectin at proportions of: 100–0%, 75–25%, 50–50%, 25–75%, and 0–100%. Combination of both polysaccharides gave continuous, homogenous and transparent films. All of analyzed films reached their state of equilibrium within the 24 h of adsorption time. Water sorption isotherms for all films had a sigmoidal shape and were not influenced by the film composition. Sorption kinetics and isotherms indicated hydrophilic character of investigated films. Statistically significant (p < 0.001) correlations were found between colour, water vapour permeability, tensile strength, elongation at break, and chemical composition (alginate and pectin) of composite films. A different internal arrangement was observed as a function of film composition.     

Development of functional pectin edible films with fillers obtained from red cabbage and beetroot

The present study aims to develop through casting, functional composite edible films based on pectin using beetroot powder and red cabbage powder as fillers obtained from by-products of plant tissue industrialisation. Physico-chemical, mechanical, thermal properties and colour stability of the films along 30 days of storage (5–45 °C; absence of light) were evaluated. The moisture and the stress at break decreased, and the intensity of red colour and the hydrophobicity increased with the presence of fillers. According to the FTIR results, there was a good compatibility between matrix and fillers in the composites. Pectin films generated an enhanced stability of red colour after 30 days of storage at 5 and 25 °C and, in general, after 16 days for 45 °C, showing their suitability to be used as colouring agents for edible food packaging applications.     

Effects of heating method and conditions on the quality attributes of black mulberry (Morus nigra) juice concentrate

Black mulberry juice was concentrated by different heating methods including conventional heating and microwave heating at different operational pressures (7.3, 38.5 and 100 kPa). The effects of each method of heating on the quality attributes of the concentrated juice were investigated. The final juice concentration of 42°Brix was achieved in 140, 120 and 95 min at 100, 38.5, and 7.3 kPa, respectively, by using a rotary evaporator. Applying microwave energy decreased the required times to 115, 95, and 60 min. The changes in anthocyanin, antioxidant, phenolic content, turbidity, pH value, and acidity during concentration were investigated. Results showed that the degradation of anthocyanins was more pronounced in rotary evaporation comparing to microwave heating method. The higher phenolic concentrations resulted in a smaller EC₅₀ value, which corresponds to a higher antioxidant activity of the mulberry extract.     

超声波处理海藻酸钠膜液对膜性能的影响

研究了超声波处理海藻酸钠膜液过程中超声功率、超声时间与间歇时间比、工作时间对可食性海藻酸钠膜性质和表面微观结构的影响。结果表明:超声波处理膜液后使膜的机械性能和阻隔性能提高,当超声功率为200W,超声时间与间歇时间比为2∶1,工作时间为20min时,膜的综合性能较佳,膜的抗拉强度为25.8MPa,断裂伸长率为29.7%,水蒸汽透过系数为1.14g.mm/m2.d.kPa,透油系数为0.41g.mm/m2.d。膜液经超声波处理后制成的膜结构致密,光滑平整。     

海藻酸钠对可食性复合膜性能的影响研究

在均匀实验设计方法得到乳清分离蛋白-酪蛋白酸钠复合蛋白膜的工艺参数的基础上,采用乳清分离蛋白、酪蛋白酸钠、海藻酸钠共混法制备可食性复合膜,研究海藻酸钠对复合膜的性能的影响。结果表明,适当浓度和比例的海藻酸钠能提高膜的机械性能和水溶性,但也降低了膜的透明度和阻隔性能。      

Flavour evaluation of three black mulberry (Morus nigra) cultivars using GC/MS,chemical and sensory data

The flavour characteristics of three black mulberry (Morus nigra) cultivars from the Aegean region of Turkey were investigated using GC/MS and sensory analysis techniques. A total of 18 flavour compounds were identified by GC/MS in the three cultivars. Total sugar content varied between 11.3 and 16.2%, pH between 3.60 and 3.80 and total acidity between 1.51 and 1.79%. The sensory assessment indicated that black mulberry has fruity, sweet, sour, musky and woody flavour notes and fruity, acid, musky, leafy and woody‐fresh aroma characteristics. The evaluation of GC/MS and sensory data revealed that ethyl linolenate was the most effective compound contributing to the unique flavour of black mulberry. © 2002 Society of Chemical Industry     

Influence of fermentation parameters on phytochemical profile and volatile properties of mulberry (Morus nigra) wine

In the present study Box–Behnken Design was employed to analyse the effects of fermentation parameters such as temperature (T _F), pH, inoculum size (I _S) and °Brix (B_X) on total phenolic concentration (TPC), total flavonoid concentration (TFC), total anthocyanin concentration (TAC), ethanol concentration (ETHC), total higher alcohol concentration (THAC) and total ester concentration (TESC) for the development of a phytochemical‐rich wine using mulberry as a substrate. The results demonstrated that fermentation parameters significantly alter the wine characteristics. Hence, a wine with excellent consumer preference (overall acceptability of 8.51) and high concentration of phytochemicals (TPC = 6014.03 ± 27.80 mg L⁻¹, TFC = 4791.35 ± 21.22 mg L⁻¹, TAC = 1480.72 ± 5.33 mg L⁻¹) as well as good aromatic properties (ETCH =82.85 ± 0.87 g L⁻¹, THAC =249.91 ± 0.31 mg L⁻¹ and TESC =52.55 ± 0.17 mg L⁻¹) with high antioxidant activity (DPPH =220.18 mmol·l⁻¹) was obtained at optimized fermentation conditions of T _F = 25°C, pH = 4.00, I _S = 10% (v /v) and B_X = 26. The results from the present study might contribute to strengthening the development of wine containing high concentrations of phytochemical compounds with attractive olfactory attributes. Copyright © 2017 The Institute of Brewing & Distilling     

Combined Effects of Proteins and Polysaccharides on Physical Properties of Whey Protein Concentrate-based Edible Films

ABSTRACT: The water-vapor permeability (WVP) and mechanical properties of edible films formed from dry blends or co-dried preparations of protein-polysaccharide powders prepared from whey protein concentrate (WPC)-45 and alginate, pectin, carrageenan, or konjac flour (WPC-45-to-polysaccharide ratio of 95:5 w/w) were investigated. Films were prepared from 8% WPC using WPC-45 (45% protein powder), consisting of 17.76 g of WPC-45 in 82.84 g of water per 100 g solution to give 8% protein w/w. Films formed from co-dried powders had lower WVP and higher tensile strength (TS), elastic modulus (EM) ( P < 0.05), and elongation (EL) than equivalent films formed from the dry blended powders. Films containing alginate had lower WVP and higher TS, EM, and EL than films containing pectin, carrageenan, or konjac flour. There is potential to alter the physical properties of hydrophilic films by combining whey protein and polysaccharide components.     

Ag+/纳米TiO2/壳聚糖复合膜制备及其对桑葚的保鲜效果

将Ag+和纳米Ti O2粒子添加至壳聚糖基体中,利用流延法制备壳聚糖基复合薄膜。研究两种粒子添加对复合薄膜的力学和透湿性能的影响,并对采用其包装的桑葚的保鲜性能进行研究。结果表明,Ag+和纳米Ti O2粒子的添加可以明显提高薄膜的力学性能,降低薄膜的水蒸汽透过量,提高对桑葚的保鲜能力。其中同时添加Ag+和纳米Ti O2粒子的复合薄膜在复合效应作用下,获得了最优的各项性能。      

海藻酸钠-果胶改性复合膜的制备及表征

以海藻酸钠(SA)和柚皮果胶(PEC)为基材,辅以添加甘油和不同种类脂质制备复合膜,通过分析各组分对膜水蒸气透过系数、过氧化值、抗拉强度等指标的影响,确定复合膜的适宜配方:SA与PEC的质量比为10/2,甘油的添加量0.3%,石蜡添加量为0.12%。以CaCl_2、BaCl_2、FeCl_3、Al_2(SO_4)_3不同交联剂对该复合膜进行改性,以CaCl_2为交联剂,CaCl_2浓度3%、交联时间3min条件下制备的海藻酸钠-果胶改性复合膜各项性能提高。以FTIR、SEM、XRD、接触角测定膜的表面结构形态和性质进行表征和测试。研究结果表明海藻酸钠-果胶复合膜各组分间的相容性好,经CaCl_2交联后显著改善膜的阻隔性能、机械性能及抗水性能,海藻酸钠-果胶改性复合膜是一种具有良好发展前景的可降解复合包装膜。     

海藻酸钙/纳米晶纤维素复合膜的制备及性能研究

采用硫酸水解脱脂棉制备纳米晶纤维素,并以浇注法制备海藻酸钙/纳米晶纤维素复合膜。通过对复合膜的机械性能、吸水性能、透湿性能和光学性能进行检测,结果表明,以此法制得的纳米晶纤维素呈棒状,直径20~40nm,长径比约为7。将纳米晶纤维素添加入膜中,复合膜的抗拉强度和断裂伸长率显著增大,而吸水性、透湿性和透光率显著减小。     

Functionality of different probiotic strains embedded in citrus pectin based edible films

The inclusion of probiotics into the packaging films has emerged as a novel approach to provide edible packaging with new functionalities. In this study, probiotic films were developed by embedding four different probiotics (Lactobacillus casei, Bifidobacterium bifidum, Lactobacillus acidophilus, and Lactobacillus rhamnosus) into citrus pectin films and their viability was checked at 25 and 4 °C for 30 days. A reduction of 0.44, 1.04, 0.32, and 1.0 log CFU g⁻¹ was observed in probiotic films containing L. casei, B. bifidum, L. acidzophilus, and L. rhamnosus respectively during drying process of film’s formation. The viability of all probiotics (except B. bifidum) was decreased from 10⁹ to 10⁶ CFU g⁻¹ in 30 days storage at 25 °C. Whereas, only 2 log reduction was observed for films stored at 4 °C during 30 days. The physical and optical properties of the films were affected slightly by inclusion of bacterial cells. The presence of live cells in films made them less resistant to elongation and less stretchable. All bacterial films inhibited the growth of L. monocytogenes by 1.5 logs compared to control. The results suggest the entrapment of probiotics in pectin can be used as an effective packaging technology for ensuring food safety.     

Production and characterization of oxidized cassava starch (Manihot esculenta Crantz) biodegradable films

Plastic is one of the most common pollutants in the environment. Therefore, the number of studies on the use of biodegradable packaging is increasing. Starch is the primary material used in the production of biodegradable plastics due to its natural abundance and high biodegradability. Yet, the strong hydrophilic character of starch presents a challenge. Therefore, the modification of its structure through oxidation may yield interesting results as the viscosity reduction. The objectives of this work were to obtain cassava (Manihot esculenta Crantz) starch oxidized with 0.8 and 2.0% active chlorine, to develop biodegradable films and characterize their mechanical properties, solubility in water, permeability to water vapor, degree of swelling, and sorption isotherms. Biodegradable films were produced with starch concentrations of 2, 3, 4, and 5% w/w and 25% glycerol (g/100 g starch) added as a plasticizer. Images of the films were obtained with an atomic force microscope and allow to observe a smooth surface and the absence of starch granules in the film produced with oxidized starches. The tensile strength of the biodegradable film produced with oxidized starch (0.8% active chlorine) was 80 MPa. The value of permeability to water vapor was 1.613 × 10⁻⁹ kg/day/m/Pa, and the average solubility was 41%. The sorption isotherms showed that biodegradable films made with oxidized starches cannot be used in environments with relative humidity below 35% or above 90%.     

可食性果蔬膜包装材料研究进展

目的:为了研究双酶复合酶解大豆分离蛋白制备大豆肽的相对分子量分布及活性片段对实验性高血压大鼠的降压效果。方法:通过单因素实验优选,采取正交实验优化复合酶的酶解工艺,以酶解液对血管紧张素转换酶(ACE)抑制率为指标优选最佳工艺;通过超滤、纳滤后得到最佳分子量片段,应用左硝基精氨酸(L-NNA)诱导大鼠高血压模型,分别给予不同剂量的活性片段进行实验。结果:双酶复合酶解的最佳条件为:在料液比为1:20 g/mL的情况下,酶解温度50℃,酶底比3.0%,酶解pH7.0条件下先用菠萝蛋白酶酶解2 h后,再以酶底比4.0%加入胰蛋白酶,控制温度为40℃、酶解pH为8.0条件下酶解4 h,大豆分离蛋白的水解度35.31%。经过高效液相对酶解液的相对分子量分布得出,大豆分离蛋白原液含有的蛋白质及多肽的相对分子质量主要区间在5000~1.0×10⁵ Da,在双酶复合酶解下,酶解液的蛋白质及多肽的相对分子质量主要区间均在500~4000 Da;通过超滤得出最佳活性片段为1000~3000 Da,药理实验表明,与模型对照组相比各组血压均有降低,且大豆肽剂量组有显著性差异(p<0.05);其中大豆肽高剂量组和卡托普利组相当。结论:双酶复合酶解制备的大豆肽相对分子量较小,活性片段对高血压大鼠模型降压作用显著。     

Development and characterization of cassava starch and soy protein concentrate based edible films

The sensory attributes, mechanical, water vapour permeability (WVP) and solubility properties of cassava starch and soy protein concentrate (SPC)‐based edible films of varying levels of glycerol were studied. Addition of SPC and glycerol up to 30% and 20%, respectively, reduced stickiness and improved colour and appearance of the films. Tensile strength (TS), elastic modulus (EM) and elongation at break (EAB) of films increased, while film solubility (FS) and WVP decreased with SPC and glycerol up to 50% and 20% level, respectively, ranging from 20.33 to 26.94 MPa (TS), 41.33 to 72.76 MPa (EM), 7.90 to 12.28 MPa (EAB), 15.07 to 31.90% (FS) and 2.62 to 4.13 g H₂O mm m^?2 day kPa (WVP). The TS, EAB and WVP were higher for the biofilms than for low‐density polyethylene and cellophane films.     

Comparative studies on the characterization and antioxidant properties of biodegradable alginate films containing ginseng extract

The physical and antioxidant properties of alginate biodegradable film incorporating white, red and extruded white ginseng extracts were investigated. No differences in moisture contents of all alginate film samples were noticeable (p > 0.05) except those film samples incorporated without ginseng extract, which had the highest moisture content. The addition of ginseng extract to alginate film decreased tensile strength and elastic modulus (p < 0.05) but increased the percent elongation at break. The presence of extracts did not significantly affect the water vapor permeability of the film samples. Alginate film containing extruded white ginseng extract at a barrel temperature of 130 °C presented the highest (61.12%) free-radical scavenging activity against the 2,2-diphenyl-1-picryhydrazyl radical (DPPH) in methanol, followed by film containing white ginseng extruded at a barrel temperature of 115 °C. Following these samples in terms of free-radical scavenging activity were film samples containing red and white ginseng extracts, respectively. These results revealed that extruded white ginseng extract has good potential to be incorporated into alginate to make antioxidant biodegradable film or coating for various food applications.     

Development and characterisation of functional cocoa (Theobroma cacao L.)-based edible films

The aim of this study was to develop functional edible films containing cocoa (Theobroma cacao L.) powder extract using alginate, pectin and chitosan in combination with proteins (whey protein isolate, soya and hemp protein). The films were examined for their physico-chemical (dry matter content, colour, thickness), mechanical (elongation at break (EAB)), bioactive (the content of total polyphenols (TPC), flavan-3-ols (F3olC), antioxidant capacity (AC)) and sensory properties. The plain alginate film exhibited the highest EAB (29.1%). The highest TPC and F3olC were determined in plain alginate (29 mg GAE/g and 2.75 mg (+)-catechin/g) and pectin (29 mg GAE/g and 2.25 mg (+)-catechin/g) films. The addition of proteins resulted in prolonged release of polyphenols and enhanced functional properties; however, the formation of protein–polyphenol complexes caused slight alterations in the bioactive composition of the films. The obtained results indicate a high potential of the developed films as functional, biodegradable form of active food packaging.