Compositional and functional properties of buttermilk: a comparison between sweet, sour, and whey buttermilk

Buttermilk is a dairy ingredient widely used in the food industry because of its emulsifying capacity and its positive impact on flavor. Commercial buttermilk is sweet buttermilk, a by-product from churning sweet cream into butter. However, other sources of buttermilk exist, including cultured and whey buttermilk obtained from churning of cultured cream and whey cream, respectively. The compositional and functional properties (protein solubility, viscosity, emulsifying and foaming properties) of sweet, sour, and whey buttermilk were determined at different pH levels and compared with those of skim milk and whey. Composition of sweet and cultured buttermilk was similar to skim milk, and composition of whey buttermilk was similar to whey, with the exception of fat content, which was higher in buttermilk than in skim milk or whey (6 to 20% vs. 0.3 to 0.4%). Functional properties of whey buttermilk were independent of pH, whereas sweet and cultured buttermilk exhibited lower protein solubility and emulsifying properties as well as a higher viscosity at low pH (pH ≤ 5). Sweet, sour, and whey buttermilks showed higher emulsifying properties and lower foaming capacity than milk and whey because of the presence of milk fat globule membrane components. Furthermore, among the various buttermilks, whey buttermilk was the one showing the highest emulsifying properties and the lowest foaming capacity. This could be due to a higher ratio of phospholipids to protein in whey buttermilk compared with cultured or sweet buttermilk. Whey buttermilk appears to be a promising and unique ingredient in the formulation of low pH foods.     

Use of ultrafiltration and supercritical fluid extraction to obtain a whey buttermilk powder enriched in milk fat globule membrane phospholipids

Whey buttermilk, a by-product from whey cream processing to butter, is rich in milk fat globule membrane (MFGM) constituents, which have technological and potential health properties. The objective of this work was to produce a dairy ingredient enriched in MFGM material, especially phospholipids, from whey buttermilk. Whey buttermilk was concentrated by ultrafiltration (10×) and subsequently diafiltered (5×) (10 kDa molecular mass cutoff membrane) at 25 °C and the final retentate was spray-dried. The whey buttermilk powder was submitted to supercritical extraction (350 bar, 50 °C) using carbon dioxide. The membrane filtration removed most of the lactose and ash from the whey buttermilk, and the supercritical extraction extracted exclusively non-polar lipids. The final powder contained 73% protein and 21% lipids, of which 61% were phospholipids. This ingredient, a phospholipids-rich dairy powder, could be used as an emulsifier in different food systems.     

Phospho- and sphingolipid distribution during processing of milk, butter and whey

Phospho‐ and sphingolipids (SPHs) were monitored upon processing of raw milk into skimmed milk, cream, butter, buttermilk, fresh cheese, acid whey, anhydrous milk fat and butterserum (=the aqueous phase of butter). These products were analysed on polar lipids, fat and dry matter and corresponding balances were calculated. It was found that polar lipids were preferentially enriched in aqueous phases like skimmed milk, buttermilk and butterserum. Significant differences in relative SPH content were observed. Tangential filtration and thermocalcic aggregation of the acid whey successfully recovered the polar lipids. With 11.5% of polar lipids on a dry matter base, representing 28.4% of the milk polar lipids and only 0.9% of the milk mass, butterserum was found to be most suitable for further purification. This could result in a food (ingredient) with enhanced technological and nutritional properties, as recent studies reveal health‐improving capacities of phospho‐ and SPHs.     

Microfiltration of buttermilk and washed cream buttermilk for concentration of milk fat globule membrane components

Buttermilk, the by-product from butter manufacture, has gained much attention lately because of the application potential of its milk fat globule membrane (MFGM) components as health ingredients. Microfiltration (MF) has been studied for buttermilk fractionation because of its ability to separate particles from dissolved solutes. However, the presence in this by-product of skim milk solids, especially casein micelles, restricts concentration of MFGM. The use of cream washed with skim milk ultrafiltrate to produce buttermilk with lower casein content was studied as well as fractionation of this buttermilk by MF. Results have shown that washing the cream prior to churning yields buttermilk with 74% less protein than normal cream buttermilk. Analysis of the protein profile of washed cream buttermilk revealed that caseins and whey proteins were the main classes of proteins removed. The MF of washed cream buttermilk resulted in permeation fluxes 2-fold higher than with normal cream buttermilk. The second separation of the cream induced high losses of phospholipids in the skim phase. However, retention of remaining phospholipids in washed cream buttermilk by the MF membrane was higher resulting in a phospholipids concentration factor 66% higher than that of normal cream buttermilk. The results presented in this study highlight the impact of casein micelles on the separation of MFGM components as well as their effect on permeation flux during MF.     

Phospholipid enrichment in sweet and whey cream buttermilk powders using supercritical fluid extraction

Milk fat globule membrane contains many complex lipids implicated in an assortment of biological processes. Microfiltration coupled with supercritical fluid extraction (SFE) has been shown to provide a method of concentrating these nutritionally valuable lipids into a novel ingredient. In the dairy industry there are several by-products that are rich in phospholipids (PL) such as buttermilk, whey, and whey cream. However, PL are present at low concentrations. To enrich PL in buttermilk powders, regular buttermilk and whey buttermilk (by-product of whey cream after making butter) were microfiltered and then treated with SFE after drying. The total fat, namely nonpolar lipids, in the powders was reduced by 38 to 55%, and phospholipids were concentrated by a factor of 5-fold. Characterization of the PL demonstrated specific molecular fatty amide combinations on the sphingosine (18:1) backbone of sphingomyelin with the greatest proportion being saturated; the most common were 16:0, 20:0, 21:0, 22:0, 23:0, and 24:0. Two unsaturated fatty amide chains, 23:1 and 24:1, were shown to be elevated in a whey cream buttermilk sample compared with the others. However, most unsaturated species were not as abundant.     

Comparison of Flavor Quality of Peanut Based Pastes and Peanut Butter by Sensory Methods

A bland flavored and light colored paste was developed to increase utilization of peanuts. This study compared flavor quality of two pastes prepared from whole and chopped peanuts, water extracted to remove flavor precursors, two commercial samples of peanut butter and a paste from raw peanuts (control). Cluster analysis was used to compare sensory scores of all samples. The premium brand peanut butter had the strongest roasted flavor while the pastes had significantly more of the beany flavor than the peanut butters but less than that in the raw control. Chopping of kernels results in the loss of roasted and sweet flavors and the introduction of cardboard, musty and metallic flavors.     

酶促奶油水解制备天然奶味香精

选用脂肪酶lipaseAY水解奶油制备天然奶味香精。在奶油与乳清粉的质量比为14:1,脂肪酶量为奶油质量的0.2%,反应温度为45℃时,其香气评分最佳。GC-MS分析结果显示:产物中脂肪酸约占80%,内酯和酯类约为20%。所制备的天然奶味香精具有浓郁的干酪风味,带有淡淡的甜奶香味,香气醇厚,口感细腻。另外,适量添加乳清粉有利于改善产物口感。     

Butter making from caprine creams: effect of washing treatment on phospholipids and milk fat globule membrane proteins distribution

A washing treatment was applied to caprine cream before churning in order to improve phospholipids and MFGM protein purification from buttermilk and butter serum. Cream obtained from a first separation was diluted with water and separated a second time using pilot plant equipment. Regular and washed creams were churned to produce buttermilk and butter, from which butter serum was extracted. The washing treatment allowed a significant decrease of the casein content. As a result, the phospholipids-to-protein ratios in washed buttermilk and butter serum were markedly increased by 2.1 and 1.7-folds respectively, which represents an advantage for the production of phospholipids concentrates. However, when compared with bovine cream, lower phospholipids-to-protein ratios were observed when the washing treatment was applied to caprine cream. A higher concentration of MFGM protein and a lower retention of phospholipids during washing treatment are responsible for the lower phospholipids-to-protein ratios in buttermilk and butter serum obtained from caprine cream. The phospholipids distribution in the butter making process was similar to the one obtained from bovine regular and washed cream. Phospholipids were preferentially concentrated in the butter serum rather than the buttermilk fraction. This simple approach permitted the production of caprine and bovine butter sera extracts containing up to 180 and 240 g phospholipids/kg sera, respectively, on a dry basis.     

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.     

SENSORY, CHEMICAL, AND PHYSICAL CHANGES IN INCREASED WATER ACTIVITY PEANUT BUTTER PRODUCTS

The effects of moisture, temperature, and storage time on the flavor characteristics of increased water activity peanut butter products were determined by sensory analysis. All three factors affected the sensory attributes of the products. At all temperatures and storage times, peanut butter products with 5.0% water added had lower roasted aroma and roasted flavor, with more off-odors and off-flavors than the 2.5% or 0.0% water added samples. Water activity and color were monitored throughout the study, and samples were evaluated for oxidation.     

可可粉末香精的感官分析及其在食品中的应用

研究了可可粉末香精作为可可粉的代替物在食品中的应用,通过感官分析从整体喜好度、香气、巧克力风味、苦味、口感五个方面对样品进行评价,并通过SPSS软件对所得数据进行方差分析.实验得出可可粉末香精能替代可可粉,同时在感官分析中没有明显差异.试验得出可可粉末香精在不同食品中可可粉的代替量,在水中溶解0.02％可可粉末香精可替代0.25％可可粉：在奶粉和牛奶中0.04％的可可粉末香精可替代0.25％的可可粉;在冰淇淋中0.05％的可可粉末香精可替代0.5％的可可粉;在饼干夹心中0.15％的可可粉末香精可代替2.5％的可可粉末.通过实验可以看出可可粉末香精在不影响产品感官品质的同时能大大降低可可粉的用量,降低产品的成本.     

Tetracycline antibiotics transfer from contaminated milk to dairy products and the effect of the skimming step and pasteurisation process on residue concentrations

The presence of antibiotics in raw milk and milk derivatives poses a threat to human health and can negatively affect the dairy industry. Therefore, the main object of this study was to investigate the transfer of oxytetracycline (OTC), tetracycline (TC), chlortetracycline (CTC) and doxycycline (DC) from raw, experimental milk contaminated with tetracyclines (TCs) to different dairy products: cream, butter, buttermilk, sour milk, whey, curd and cheese. Additionally the effect of the skimming process on TCs concentrations was tested, as well as the influence of low-temperature long-time pasteurisation. The analyses of TCs in milk and dairy products were performed by an LC-MS/MS method. In order to determine TCs residues in dairy products, an analytical method was developed with the same extraction step for all matrices. TCs molecules were inhomogenously distributed between the milk derivative fractions. The highest concentrations were determined in curd and cheese in the ranges 320–482 µg/kg and 280–561 µg/kg, respectively. Low levels of TCs in butter and whey were observed (11.8–41.2 µg/kg). TCs were found in sour milk (66.0–111 µg/kg), cream (85.0–115 µg/kg) and buttermilk (196–221 µg/kg) at much higher levels than in butter and whey, but lower than in curd and cheese. During the skimming process, the highest yield of cream was obtained after the raw milk was held at 2–8°C for 24 h. The differences in concentrations of TCs between whole milk and skimmed milk, expressed as percentages of recovery, were below 19% (recoveries in excess of 81%). The highest content was observed in milk and cream skimmed at 2–8°C. The degradation percentages for TCs during the pasteurisation process (63°C for 30 min) were below 19%.