Transglutaminase-mediated incorporation of whey protein as fat replacer into the formulation of reduced-fat Iranian white cheese: physicochemical,rheological and microstructural characterization

The effects of transglutaminase treatment (0–2 units/g milk protein) on the chemical composition, textural characteristics, proteolysis and yield of reduced-fat Iranian white cheese (milk fat: 0.4–1.4% w/w) incorporated with whey proteins (0–6 g/L milk) were investigated. Enzyme-mediated inclusion of whey proteins in the reduced-fat cheese caused a noticeable increase in moisture to protein (M:P) ratio with concomitant decease in the hardness rheological parameters of fracture stress and Young’s and storage (G’) moduli. However, increase in concentrations of whey proteins or/and transglutaminase enzyme above a critical level led to formation of a cheese matrix with lower moisture content and greater values of hardness indices. Whey protein addition and transglutaminase treatment resulted in the same trends of changes in proteolysis rate and cheese yield as in cheese softness. Response surface method (RSM) suggested that the enzymatic incorporation of 4.2 g deliberately added whey proteins to 1 L of milk (1.04% w/w fat) into the cheese matrix using 0.833 unit transglutaminase per gram milk protein would provide a reduced-fat product with the softest texture and the highest yield. The scanning electron micrographs showed formation of honeycomb structures in the protein matrix of the reduced-fat sample with optimum formulation.     

滑菇在冰淇淋生产中的增稠稳定作用

将滑菇按料水比1∶3（m/m）加水混合并匀浆处理后用于冰淇淋的生产,研究其对冰淇淋混合料的增稠稳
定作用。以冰淇淋的抗融性、膨胀率及感官评分为考察指标,通过正交试验筛选滑菇最佳处理方法及冰淇淋最佳配
方,当滑菇在绝对压强0.15 MPa条件下煮制25 min,其他条件为滑菇浆添加量4%、羧甲基纤维素钠（CMC-Na）添
加量0.1%、单甘酯添加量0.4%时,产品综合品质最佳,无需添加明胶仍然具有良好的光洁度及保形性。比较滑菇
冰淇淋与传统牛奶冰淇淋的脂肪失稳度、硬度、黏度、显微结构等方面变化,结果表明滑菇冰淇淋优于传统牛奶冰
淇淋,其组织柔滑、口感细腻、膨胀率好、抗融性适当。     

High hydrostatic pressure modification of whey protein concentrate for improved body and texture of lowfat ice cream

Previous research demonstrated that application of high hydrostatic pressure (HHP), particularly at 300 MPa for 15 min, can enhance foaming properties of whey protein concentrate (WPC). The purpose of this research was to determine the practical impact of HHP-treated WPC on the body and texture of lowfat ice cream. Washington State University (WSU)-WPC was produced by ultrafiltration of fresh separated whey received from the WSU creamery. Commercial whey protein concentrate 35 (WPC 35) powder was reconstituted to equivalent total solids as WSU-WPC (8.23%). Three batches of lowfat ice cream mix were produced to contain WSU-WPC without HHP, WSU-WPC with HHP (300 MPa for 15 min), and WPC 35 without HHP. All lowfat ice cream mixes contained 10% WSU-WPC or WPC 35. Overrun and foam stability of ice cream mixes were determined after whipping for 15 min. Ice creams were produced using standard ice cream ingredients and processing. The hardness of ice creams was determined with a TA-XT2 texture analyzer. Sensory evaluation by balanced reference duo-trio test was carried out using 52 vol.nteers. The ice cream mix containing HHP-treated WSU-WPC exhibited the greatest overrun and foam stability, confirming the effect of HHP on foaming properties of whey proteins in a complex system. Ice cream containing HHP-treated WSU-WPC exhibited significantly greater hardness than ice cream produced with untreated WSU-WPC or WPC 35. Panelists were able to distinguish between ice cream containing HHP-treated WSU-WPC and ice cream containing untreated WPC 35. Improvements of overrun and foam stability were observed when HHP-treated whey protein was used at a concentration as low as 10% (wt/wt) in ice cream mix. The impact of HHP on the functional properties of whey proteins was more pronounced than the impact on sensory properties.     

Technological and sensorial properties of liquid nitrogen ice cream enriched with protein from brewing waste (trub)

Debittered trub (brewing waste) is an important source of protein source (70.26%). Trub and whey protein were used for 5% protein enrichment of ice cream frozen by liquid nitrogen. Three formulations were elaborated: ice cream standard (ICS), ice cream with whey protein (ICW) and ice cream with trub (ICT). Chemical composition, rheological properties, texture, overrun, melting rate, scanning electron microscopy and a sensorial test were performed. Results showed that ICT presented a higher viscosity, obtained on the upward curve up to 6.76 Pa s⁻¹, consistency index (22.96 (Pa s⁻¹)ⁿ), hysteresis area (140.40 mPa s⁻¹) and hardness (31113.33 g) but a lower melting rate (0.38 g min⁻¹), overrun (13.92%) and sensorial acceptability than the other formulations. The addition of trub debittered for protein enrichment improved ice cream properties and demonstrated that it could be used as a food ingredient.     

The effect of soy protein concentrate addition on the physical, chemical, and sensory properties of strawberry flavored ice cream

The effect of soy protein concentrate (0, 1.5, 3, and 4.5%) on the physical, chemical, and sensory properties of strawberry flavored (0, 0.01 and 0.02%) ice cream samples was examined. All samples were analyzed for pH, titratable acidity, total solids, nitrogen, fat, ash, overrun, viscosity, meltdown, Hunter L-, a-, b- values, flavor, body and texture, and appearance. Substituting soy protein concentrate (SPC) in ice cream formula for non-fat dry milk (NFDM) positively influenced the nitrogen content, viscosity values, and melting and appearance properties of the ice cream samples while overrun values and flavor scores were negatively affected. SPC could be incorporated into the ice cream formula in the range of 1.5–3% devoid of significantly diminishing the physical, chemical, and sensory properties.     

Rheological properties of reduced-fat and low-fat ice cream containing whey protein isolate and inulin

Instrumental analyses were used to evaluate the rheological properties of regular (10%), reduced-fat (6%) and low-fat (3%) ice cream mixes and frozen ice creams stored at −18 °C. The reduced-fat and low-fat ice creams were prepared using 4% whey protein isolate (WPI) or 4% inulin as the fat replacement ingredient. The composition, colour, apparent viscosity, consistency coefficient, flow behaviour index, hardness and melting characteristics were measured. No effect of WPI or inulin was obtained on the colour values. Compared with regular ice cream, WPI changed rheological properties, resulting in significantly higher apparent viscosities, consistency indices and greater deviations from Newtonian flow. In addition, both hardness and melting resistance significantly increased by using WPI in reduced-fat and low-fat ice creams. Inulin also increased the hardness in comparison to regular ice cream, but the products made with inulin melted significantly faster than the other samples.     

双蛋白对冰淇淋品质的影响

本文研究了不同浓度的双蛋白的起泡性、泡沫稳定性、乳化性和乳化稳定性。并以不同比例的添加量(0、5%、10%、15%、20%)加入到冰淇淋中,通过测定料液的黏度、冰淇淋的硬度、融化率、膨胀率等指标,研究双蛋白添加量对冰淇淋品质的影响。结果表明,蛋白起泡性和泡沫稳定性随双蛋白溶液浓度增加,起泡性先上升后下降,泡沫稳定性先上升后保持稳定;蛋白乳化性和乳化稳定性随双蛋白溶液浓度的增加先上升后保持不变。随着双蛋白添加量的增加,冰淇淋料液黏度呈先上升后下降趋势,硬度呈上升趋势,融化率呈下降趋势;当添加量在0~10%的范围时,膨胀率先下降后上升;当添加量大于10%后,膨胀率和感官评分开始下降,冰淇淋品质变差。此外,10%双蛋白添加量同对照组感官评分无显著差异,口感可以被消费者接受,选择双蛋白的添加量为10%。     

The microstructural,melting, rheological,and sensorial properties of high-overrun frozen desserts

Air incorporated during dynamic freezing influences the development of the microstructure and the final texture of frozen desserts. Frozen desserts were manufactured with 100–175% overrun from a constant ice cream mix formulation. Microstructural elements (fat, air, and ice phases) of the frozen desserts were then investigated and related to the melting, rheological, and sensory properties of the product. Mean ice crystal and air cell size were found to decrease with increasing overrun, and the extent of fat destabilization increased. Frozen desserts manufactured with higher overrun had slower drip-through rate and better shape retention after melting at ambient conditions, demonstrating that fat destabilization and the interplay of fat, air, and serum phases affect the melting behavior. Structural elements also influenced the rheological behavior, as measured by oscillatory thermo-rheometry. Frozen desserts had similar rheological properties at temperatures below the freezing point due to the presence of ice, and the values of G′ and G″ (solid-like and viscous-like character, respectively) increased with increasing overrun above the freezing point, corresponding to a more solid-like structure. Slight differences in sensory denseness and breakdown were detected, but sensory texture was not significantly different for the frozen desserts studied. This study provided insights into the role of air in ice cream and frozen desserts, and its influence on product texture.     

不同类型稳定剂和乳化剂对冰淇淋品质特性的影响

本文研究了不同类型的稳定剂和乳化剂在冰淇淋中的作用,以三种代表性的不同类型的稳定剂:卡拉胶（离子型多糖）、瓜尔豆胶（非离子型多糖）和明胶（蛋白质）,以及具有不同亲水亲油性的乳化剂:单硬脂肪酸甘油酯（Glyceryl Monostearate, MG,HLB=3.8）和吐温80（HLB=15）作为研究对象,以冰淇淋的物理特性（粘度、膨胀率与融化率）和感官（粘稠度、顺滑性、口融性与颗粒感）为指标,讨论了稳定剂和乳化剂对冰淇淋品质的影响。结果表明,与吐温80相比,加入MG的冰淇淋膨胀率更高,抗融性更好,二者对浆料粘度的作用无显著性差异（P<0.05）;三种稳定剂均可增大冰淇淋浆料的粘度,其中,卡拉胶较瓜尔豆胶和明胶对浆料粘度的影响差异显著（P<0.05）,抗融性最强,瓜尔豆胶对膨胀率影响最大。其中MG与卡拉胶复配所得浆料粘度和抗融性最佳,分别为898.35 cp,融化率4.74%;与瓜尔豆胶复配所得冰淇淋膨胀率最高为66.95%。在此基础上,以MG作为乳化剂,复配瓜尔豆胶和卡拉胶,研究不同复配比例的稳定剂在冰淇淋中的作用。结果表明,稳定剂总添加量为0.25%时,卡拉胶与瓜尔豆胶的质量比为1:1.5,冰淇淋的浆料粘度可达1036.5 cp,融化率为17.4%,感官评分最高。     

EFFECTS OF COTTAGE CHEESE WHEY ON THE PROPERTIES OF ICE MILK1

Liquid cottage cheese whey was used in the production of slightly acidic ice milk mixes at levels of 0, 16, 31, 46, and 61%. Because of precipitation problems, whey levels of 46 and 61% could not be used. Consistency index (K) of the ice milk mix was not significantly (p > 0.05) influenced by increasing the cottage cheese whey level from 0 to 31.0%, and all ice milk mixes evaluated exhibited pseudoplastic behavior (flow behavior indices or n value less than unity). Whey at an intermediate level (16%) resulted in slightly higher overrun compared with ice milk at 0 or 31% whey. Further, sensory ratings (flavor, texture, sourness) for ice milk with 16% whey were not different (p > 0.05) from those of control ice milk. While increasing the level of whey to 31% appeared to slightly reduce sensory acceptance of the ice milk, this apparent difference was not significant (p > 0.05). Overall, 46.0% of the panelists preferred the ice milk without whey compared with 32.5% for 16.0% whey and 21.5% for 31% whey formulation.     

The functional, rheological and sensory characteristics of ice creams with various fat replacers

The effects of fat replacers (Simplesse® D-100, N-Lite D, and inulin) on the melting characteristics, overruns, hardness, rheological parameters and sensory attributes of reduced (RF, 60.0 g/kg), low (LF, 40.0 g/kg), and nonfat (NF, 1.0 g/kg) ice creams were investigated. The magnitudes of the melting rates were in the order RF>LF>NF for samples that contained Simplesse® D-100 or inulin, but the reverse order was found for samples with N-Lite D. The nonfat ice creams had lowest overrun values of around 10%. Inulin-containing ice creams possessed higher overrun values than others ( P  > 0.05). The use of fat replacer decreased the hardness of ice creams. All ice cream samples showed pseudoplastic (shear-thinning) behavior. The addition of N-Lite D and inulin decreased the flow behaviour index of ice cream samples. The reduced and low fat ice cream samples were rated as similar to the control by a sensory panel. On the other hand, no correlations ( P  > 0.05) were observed between rheological parameters and sensory texture and mouthfeel.     

High hydrostatic pressure modification of whey protein concentrate for use in low-fat whipping cream improves foaming properties

Whey is the inevitable by-product of cheese production. Whey can be incorporated into a variety of foods, but little has been done to investigate its suitability in whipping cream. The objective of this work was to evaluate the foaming properties of selected low-fat whipping cream formulations containing whey protein concentrate (WPC) that did or did not undergo high hydrostatic pressure (HHP) treatment. Fresh whey was concentrated by ultrafiltration, pasteurized, and standardized to 8.23% total solids and treated with HHP at 300 MPa for 15 min. Viscosity, overrun, and foam stability were determined to assess foaming properties. Sensory evaluation was conducted with 57 panelists using a duo-trio difference test. The optimal whipping time for the selected formulations was 3 min. Whipping cream containing untreated WPC and HHP-treated WPC resulted in greater overrun and foam stability than the control whipping cream without WPC. Panelists distinguished a difference between whipping cream containing untreated WPC and whipping cream containing HHP-treated WPC. High hydrostatic pressure-treated WPC can improve the foaming properties of low-fat whipping cream, which may justify expansion of the use of whey in whipping cream and application of HHP technology in the dairy industry.     

Antioxidant capacity and functionality of oleaster (Elaeagnus angustifolia L.) flour and crust in a new kind of fruity ice cream

In this study, the influence of milled crust and flour from oleaster (Elaeagnus angustifolia L.) separately added at different levels (1%, 2% and 3%) on the physical, chemical, sensory, colour properties and antioxidant properties of ice creams were investigated. The increment of crust and flour level caused an increase of dry matter, acidity, viscosity, first dripping, complete melting and vitamin C content. Flour increased overrun values in ice cream. Our results indicated that lyophilised oleaster extracts contain remarkable phenolic compounds. It was observed that lyophilised oleaster extracts exhibited a moderate in vitro antioxidant capacity. The addition of oleaster flour and crust positively affected sensory properties. The sensory results showed that ice cream containing 2% oleaster flour was the highest scored by the panellists. Oleaster flour and crust increased the sweetness of ice cream samples. These results showed that considerable nutritive and functional improvement could be attained by the addition of oleaster flour to ice cream formulation so that it could be used as natural antioxidants in ice cream as a source of flavour with complacency.     

EFFECT OF MILK PROTEINS AND STABILIZER ON ICE MILK QUALITY

Ice milk mixes were made with and without stabilizer/emulsifier as well as with and without milk protein isolate (sodium caseinate or whey protein isolate). The mixes were evaluated for rheological, freezing, melting, and sensory properties. Adding a stabilizer/emulsifier blend to ice milk changed its physical properties more than adding milk protein isolates. The mixes with stabilizer/emulsifier exhibited increased viscosity and chewiness and decreased drainage rate, iciness, and vanilla flavor intensity. The mixes with added caseinate exhibited increased viscosity compared with those with added whey protein isolate. Overall, the quality of ice milk mix was more dependent on stabilizer/emulsifier addition than on milk protein isolate addition.     

影响冰淇淋融化速率的质构因素

应用统计学模型研究了影响冰淇淋融化速率的质构因素。样品配方中采用3种甜味剂和3个水平的蔗糖酯。测定的因素包括凝冻前浆料的黏度,成品冰淇淋的各项TPA质构参数以及样品的膨胀率。由多元线性回归方程得出冰淇淋的黏附性、浆料的黏度、成品的膨胀率等因素对融化率的影响较大。     

Influence of the partial substitution of skim milk powder for soy extract on ice cream structure and quality

In the present work, we aimed to study the influence of the partial substitution of skim milk powder for soy extract (SE) on the quality characteristics of ice cream. Physical and chemical composition, rheologic behavior, overrun value, hardness, melting characteristics, and sensory properties were evaluated at levels of 0, 10, 20, and 30% substitution. The size and distribution of the ice crystals were measured before and after heat shock testing. The addition of a SE instead of skim milk powder promoted an improvement in the protein content, pH, and consistency coefficient, and it reduced the carbohydrate content of the ice cream mix. Treatment with a 10% substitution led to the highest overrun value and to the lowest hardness value. Ice cream containing SE in the formulation exhibited a greater melting resistance, a larger amount of small ice crystals, and a lower amount of ice crystal growth after heat shock. SE could be incorporated into ice cream formulation until the substitution level of 20% devoid affects its sensory acceptance.     

奇亚籽皮多糖对冰淇淋乳化稳定性及品质的影响

考察不同质量浓度（0.5、1.0、1.5、2.0 mg/mL）的奇亚籽皮多糖作为乳化稳定剂在冰淇淋产品中的应用,通过对冰淇淋浆料稳定性和冰淇淋膨胀率、融化率、质构、气泡分布及结构特性等指标的测定,考察不同质量浓度奇亚籽皮多糖对冰淇淋品质的影响规律。结果表明：随着奇亚籽皮多糖质量浓度的增加,冰淇淋浆料的稳定性及冰淇淋的膨胀率、质构特性（弹性、黏附性、咀嚼性）提高,融化率和硬度降低,冰淇淋中气泡分布更加均匀,气泡直径均一,数量增多。添加奇亚籽皮多糖可提高冰淇淋浆料的表观黏度,冰淇淋浆料均表现出假塑性非牛顿流体。与空白冰淇淋样品对比,添加0.5 mg/mL质量浓度的奇亚籽皮多糖冰淇淋,其各性质测定结果略有改善,但质量浓度大于1.5 mg/mL时,可显著提高冰淇淋抗融性及稳定性,降低其硬度,改善其微观结构,气泡分布更均匀,使冰淇淋组织更加光滑。相较于空白冰淇淋样品,奇亚籽皮多糖的添加对冰淇淋的品质特性、结构特性及稳定性方面均有显著改善作用,为奇亚籽皮多糖应用于冰淇淋食品生产提供一定科学依据。     

A modified ice cream processing routine that promotes fat destabilization in the absence of added emulsifier

The quality of ice cream made without added emulsifier using a modified processing routine was compared to ice cream made conventionally with and without added emulsifier. “Two-phase process” ice cream was created by preparing two separate phases; emulsion (fat, some protein, water) and solution (remaining protein, sugar, corn syrup solids, stabilizer, water) and combining them just before freezing. Quality indicators included percent fat destabilized, overrun and meltdown rate. Conventional process ice cream containing emulsifier exhibited a high degree of fat destabilization, high overrun and slow meltdown. Ice cream produced conventionally without emulsifier underwent little fat destabilization, had low overrun and melted rapidly. Ice cream produced by the two-phase process showed good fat destabilization and slow meltdown with moderate overrun, suggesting this method was successful in promoting desirable structure formation without added emulsifier.