Utilization of Lactoferrin as an Iron-Stabilizer for Soybean and Fish Oil

ABSTRACT: We investigated the oxidative stability of soybean oil and fish oil fortified with iron solubilized by lactoferrin (FeLF). Oxidative stability was evaluated by measuring the induction period of the Rancimat test. The induction time of soybean oil added FeCl₃ was decreased; however, that of added FeLF was not. This effect of lactoferrin was also observed in the iron-catalyzed oxidation offish oil at temperatures ranging from 50°C to 120°C, and at concentrations of iron ranging from 0 to 500 ppm. Thus, lactoferrin is considered useful as a natural iron stabilizer for food products containing polyunsaturated fatty acids.     

Screening of Bifidobacterium spp. based on in vitro growth responses to bovine lactoferrin

In the present study, we investigated the in vitro growth responses of fourteen strains of four Bifidobacterium spp. (Bifidobacterium infantis, B. breve, B. bifidum, B. longum) against bovine lactoferrin (bLf) at various concentrations. Bacterial strains were grown in deMan, Rogosa and Sharpe (MRS) broth with or without bLf, and growth was monitored by measuring absorbance at 660 nm. A dose‐dependent and strain‐dependent growth response was observed. Bifidobacterium spp. were ranked into high, medium and low according to their calculated relative growth response levels against lactoferrin (Lf). Strains showed better growth responses against holo‐type Lf. However, no inhibitory effects at high concentrations (4 mg mL^?1) or with apo‐type Lf were observed. These results strongly suggest that the growth response of Bifidobacterium spp. against bLf may be a selection criterion for their use in fermented products. In addition, use of holo‐type Lf in fermented food products may be more effective for probiotic growth, and could also be used as a source of iron to the host.     

Oxidative stability of mayonnaise and milk drink produced with structured lipids based on fish oil and caprylic acid

The oxidative stabilities of traditional fish oil (FO), randomized lipids (RFO), or specific structured lipids (SFO) produced from fish oil were compared when incorporated into either milk drink or mayonnaise. Furthermore, the effect of adding the potential antioxidants EDTA (240 mg/kg) or lactoferrin (1000 mg/kg) to the milk drink based on SFO was investigated. The lipid type significantly affected the oxidative stability of both mayonnaises and milk drinks: The oxidative stability decreased in the order RFO>FO>SFO. The reduced oxidative stability in the SFO food emulsions could not be ascribed to a single factor, but was most likely influenced by the structure of the lipids and differences in the processes used to produce and purify the lipids. In milk drinks based on SFO, EDTA slightly reduced oxidation, while lactoferrin did not exert a distinct antioxidative effect.     

Importance of instrumental and sensory analysis in the assessment of oxidative deterioration of omega‐3 long‐chain polyunsaturated fatty acid‐rich foods

Omega‐3 long‐chain polyunsaturated fatty acids (LC PUFA) positively influence human health. Their main dietary source is fish, especially fish oil. Owing to low fish consumption in many Western countries the average intake of omega‐3 LC PUFA is below the recommended level. This raises interest in diet supplementation and food enrichment with fish oil. However, due to a high degree of unsaturation fish oil is extremely susceptible to oxidation. Oxidation of fish oil increases when added to food products, which may be enhanced by some antioxidants, under certain conditions. For quality control of omega‐3 LC PUFA‐containing foods adequate and combined methods of oxidation assessment should be used, beginning from the raw material and continuing during processing, storage and distribution. To achieve this goal correlation of instrumental and sensory methods with multivariate data analysis may give the best results. In this paper problems of oxidation of fish oil and fish oil‐containing foods, as well as methods for its assessment, are reviewed. Copyright © 2006 Society of Chemical Industry     

牛初乳中乳铁蛋白的分离及纯化

乳铁蛋白(Lactoferrin,简称Lf)作为一种糖蛋白,主要存在于哺乳动物的各种外分泌物中,如乳汁、眼泪、唾液等,乳汁尤其是初乳中Lf的含量很高犤1犦。本文通过盐析法和有机溶剂沉淀法从牛初乳中分离出乳铁蛋白,并应用酶联免疫法鉴定各步骤中分离的乳铁蛋白,获得的乳铁蛋白的相对分子量为75,000Da。      

Effect of bovine lactoferrin addition to milk in yogurt manufacturing

The aim of this work was to study the effect of milk supplementation with lactoferrin of different iron saturation on the manufacturing and characteristics of yogurt. Bovine lactoferrin was added at concentrations of 0.5, 1, and 2 mg/mL in the holo (iron saturated) and apo (without iron) forms. Some physicochemical properties, such as pH, concentration of lactic acid, and texture of supplemented yogurts, were determined throughout the shelf-life period storage (28 d) at 4°C. We also evaluated the stability of lactoferrin in supplemented yogurt throughout the storage time. The supplementation of milk with bovine lactoferrin did not greatly affect the physical properties of the yogurt, though apo-lactoferrin slightly delayed the decrease of pH. This could be attributed to the partial inhibition observed on the growth of Streptococcus thermophilus. The integrity and immunoreactive concentration of lactoferrin, determined by Western blotting and noncompetitive ELISA, respectively, remained constant throughout the shelf life of yogurt.     

乳铁蛋白的分离及纯化

乳铁蛋白 (Lactoferrin ,简称Lf)作为一种糖蛋白 ,主要存在于哺乳动物的各种外分泌物中 ,如乳汁、眼泪等 ,乳汁尤其是初乳中Lf的含量很高[1] 。Lf是一种多功能蛋白质 ,不仅具有广谱的抗菌作用 ,而且还能够增强机体的抗病毒、抗感染、抗肿瘤的能力和免疫能力。因此 ,从来源丰富的牛初乳中提取出Lf,把它作为功能性成分应用于食品行业 ,具有广阔的应用和开发前景。本文通过盐析法和层析法从牛初乳中分离出乳铁蛋白 ,并应用酶联免疫法 (ELISA)检测不同分离纯化方法所获得的乳铁蛋白的含量 ,并用电泳分析其纯度。所获得的乳铁蛋白的分子质量为 780 0 0u ,其纯度大约为 92 %。     

Sensory and molecular characterisation of human milk odour profiles after maternal fish oil supplementation during pregnancy and breastfeeding

The odourant profile of human milk has been proposed to be modulated by the composition of the maternal diet via the transference of specific food aromas to the milk, such that neonates are exposed to these aromas and are prepared for latter acceptance of specific diets. For that reason the aim of the present study was to investigate whether specific fish oil odour constituents translate into human milk. To achieve this goal, human sensory analyses and qualitative and quantitative instrumental determination of fish oil odourants were performed on the fish oil, as well as on human milk obtained from mothers after long-term fish oil supplementation in comparison to a control group. Sensory and analytical data showed that no statistically significant modification occurred from fish oil intervention.     

Effect of iron saturation on the recovery of lactoferrin in rennet whey coming from heat-treated skim milk

This study aimed to determine the effect of thermal treatments on the recovery of lactoferrin in whey coming from rennet-coagulated skim milk. The impact of lactoferrin iron saturation was also assessed using skim milk spiked with different lactoferrin iron forms. The recovery of lactoferrin in the rennet whey fraction was determined by reverse-phase HPLC. One- and 2-dimensional sodium dodecyl sulfate PAGE analyses were performed on rennet curds to characterize the protein interactions involving lactoferrin in heated milk. The extent of lactoferrin recovered in the whey fraction was found to reduce as the heating temperature increased. The binding of iron by lactoferrin improved its thermal stability and its recovery in the whey fraction. Poly-acrylamide gel electrophoresis results showed that the association of lactoferrin in the unheated milk rennet curd involved noncovalent interactions, whereas upon heating, lactoferrin also interacted via an intermolecular disulfide link. Depending on the severity of the heat treatment, lactoferrin aggregates with Cys-containing proteins (β-lactoglobulin, α-lactalbumin, α_s2-casein, and κ-casein) occurred by intermolecular thiol/disulfide exchange reactions. These noncovalent and covalent interactions explained the lower recovery of lactoferrin in heated milk.     

The age of cows as a factor shaping the antioxidant level during a nutritional experiment with fish oil and linseed supplementation for increasing the antioxidant value of milk

BACKGROUND: So far, in research studies, the age of cows has not been considered as a factor that may influence the changes in the content of milk ingredients with antioxidant properties modified by the feed supplementation. The aim of this study was to determine the influence of supplementation on the content of ingredients having antioxidant properties and to determine the influence of the age of cows taking part in the experiment on these changes. The experiment was conducted using 20 Polish Holstein Friesian cows, 10 primiparous and 10 multiparous. The combined supplementation of fish oil and linseed constituted the experimental factor. RESULTS: The milk of primiparous cows after 21 days of supplementation was characterised by a higher content of C18:1 trans ‐11, C18:2 cis ‐9, trans ‐11, α‐retinol, α‐tocopherol and β‐lactoglobulin compared to the milk of multiparous cows, in which a higher level of lactoferrin, C20:5 and β‐carotene was recorded. In both groups an increase in the total antioxidant status was noted (a higher level in the milk of primiparous cows). CONCLUSIONS: Modification of the diet of cows with fish oil and linseed significantly influenced antioxidant properties of their milk; however, the response of multiparous and primaparous cows was noticeably different to the supplement introduced. Copyright © 2012 Society of Chemical Industry     

Iron absorption and haemoglobin status of rats fed a ferrous bisglycinate‐fortified growing‐up milk

BACKGROUND: Infants and toddlers aged 6–24 months constitute one of the groups at highest risk of iron deficiency. A promising alternative for ferrous sulfate (FS) might be ferrous bisglycinate (FeAAC), which is less likely to cause sensory changes in the food vehicle. This work aims to compare the effect of FeAAC with that of FS, when added to a growing‐up milk, on the iron and haemoglobin status in weanling rats using a depletion–repletion model. RESULTS: After the repletion period no significant differences were found in iron absorption, Hb concentration, Hb iron, Hb regeneration efficiency (HRE), mean corpuscular volume (MCV), mean corpuscular Hb (MCH), mean corpuscular Hb concentration (MCHC), serum iron, total iron binding capacity (TIBC), transferrin saturation (TS), and ferritin between the group fed a growing‐up milk fortified with FS and the group fed one fortified with FeAAC. Furthermore, iron absorption, HRE, MCV, MCH, serum iron, and TS were significantly (P < 0.05) higher in groups fed either type of iron‐fortified growing‐up milk compared to the control group (AIN‐93G diet). CONCLUSION: A growing‐up milk supplemented with FeAAC showed an improvement in the iron absorption and haemoglobin status at the same level as those of FS. Copyright © 2009 Society of Chemical Industry     

Effect of Soybean Lecithin on Iron‐Catalyzed or Chlorophyll‐Photosensitized Oxidation of Canola Oil Emulsion

The effect of soybean lecithin addition on the iron‐catalyzed or chlorophyll‐photosensitized oxidation of emulsions consisting of purified canola oil and water (1:1, w/w) was studied based on headspace oxygen consumption using gas chromatography and hydroperoxide production using the ferric thiocyanate method. Addition levels of iron sulfate, chlorophyll, and soybean lecithin were 5, 4, and 350 mg/kg, respectively. Phospholipids (PLs) during oxidation of the emulsions were monitored by high performance liquid chromatography. Addition of soybean lecithin to the emulsions significantly reduced and decelerated iron‐catalyzed oil oxidation by lowering headspace oxygen consumption and hydroperoxide production. However, soybean lecithin had no significant antioxidant effect on chlorophyll‐photosensitized oxidation of the emulsions. PLs in soybean lecithin added to the emulsions were degraded during both oxidation processes, although there was little change in PL composition. Among PLs in soybean lecithin, phosphatidylethanolamine and phosphatidylinositol were degraded the fastest in the iron‐catalyzed and the chlorophyll‐photosensitized oxidation, respectively. The results suggest that addition of soybean lecithin as an emulsifier can also improve the oxidative stability of oil in an emulsion.     

Camel milk lactoferrin reduces the proliferation of colorectal cancer cells and exerts antioxidant and DNA damage inhibitory activities

Lactoferrin (Lf), the main iron-binding protein of milk, has biological activities. We have evaluated the potential of camel milk lactoferrin for its ability to inhibit the proliferation of the colon cancer cell line, HCT-116, in vitro, DNA damage and its antioxidant activities for the first time. The antioxidant capacity of Lf was evaluated by different assays, including ferric-reducing/antioxidant power assay (FRAP), free radical-scavenging activity (DPPH), nitric oxide (NO) radical-scavenging assay, total antioxidant activity and DNA damage, compared with vitamin C and rutin.     

Lactoferrin supplementation to Holstein calves during the preweaning and postweaning phases

Sixty Holstein calves (30 bulls, 30 heifers) were used to examine the effects of supplemental lactoferrin on feed intake, growth, and health during the preweaning and postweaning periods. One of 3 levels of lactoferrin was supplemented from 3 to 56 d in either whole milk or water to produce 3 dietary treatments: 1) 0 g/d, 2) 0.5 g/d, and 3) 1 g/d. Whole milk (3.8 L/d) containing lactoferrin supplements was fed from bottles until weaning at 35 d. From d 36 to 56, lactoferrin supplements were added to water (15 to 25 mL) and fed from bottles. Lactoferrin supplementation had no effect on feed intake, body weight, average daily gain, heart girth, body temperature, fecal scores, respiratory scores, or haptoglobin concentrations. Calves were housed in individual pens in either an open-sided barn or hutches. Calves raised in the barn consumed more calf starter and therefore grew better than calves raised in hutches. Under the conditions of this study, lactoferrin supplementation was not beneficial. Further research is needed to fully elucidate the role of lactoferrin, and possible benefits during different feeding conditions or milk sources.     

Effects of Green Tea Extract and α‐Tocopherol on the Lipid Oxidation Rate of Omega‐3 Oils,Incorporated into Table Spreads,Prepared using Multiple Emulsion Technology

Abstract: This study examined the effectiveness of fat and water soluble antioxidants on the oxidative stability of omega (ω)‐3 rich table spreads, produced using novel multiple emulsion technology. Table spreads were produced by dispersing an oil‐in‐water (O/W) emulsion (500 g/kg 85 camelina/15 fish oil blend) in a hardstock/rapeseed oil blend, using sodium caseinate and polyglycerol polyricinoleate as emulsifiers. The O/W and oil‐in‐water‐in‐oil (O/W/O) emulsions contained either a water soluble antioxidant (green tea extract [GTE]), an oil soluble antioxidant (α‐Tocopherol), or both. Spreads containing α‐Tocopherol had the highest lipid hydroperoxide values, whereas spreads containing GTE had the lowest (P < 0.05), during storage at 5 °C, while p‐Anisidine values did not differ significantly. Particle size was generally unaffected by antioxidant type (P < 0.05). Double emulsion (O/W/O) structures were clearly seen in confocal images of the spreads. By the end of storage, none of the spreads had significantly different G′ values. Firmness (Newtons) of all spreads generally increased during storage (P < 0.05). Practical Application: Lipid oxidation is a major problem in omega‐3 rich oils, and can cause off‐odors and off‐flavors. Double emulsion technology was used to produce omega‐3 enriched spreads (O/W/O emulsions), wherein the omega‐3 oil was incorporated into the inner oil phase, to protect it from lipid oxidation. Antioxidants were added to further protect the spreads by reducing lipid oxidation. Spreads produced had good oxidative stability and possessed functional (omega‐3 addition) properties.     

Variation of six bioactive milk proteins from milk from Chinese commercial dairy farms: Effect of season,farm, breed and udder health status

The study investigated potential changes in bioactive milk proteins in relation to the season, breed, farm and udder health status. Nine hundred and sixty bulk milk samples from 12 commercial farms in northwest China were collected during 2020–2021. Six bioactive proteins including fraction of β-casein proteins, α-lactalbumin, β-lactoglobulin, lactoferrin (Lf) and osteopontin were evaluated. It was found that most proteins (with exception of β-casein A1) of Jersey cows are significantly higher than Holstein cows. Most bioactive proteins demonstrated seasonal variation, and some exhibited geographical variation (with exception of whey albumins). The milk somatic cell count showed a positive correlation with immune proteins such as Lf.     

Effects of supplementation of dairy cattle with fish oil on silage intake, milk yield and milk composition

The effects of level of fish oil inclusion in the diet on grass silage intake, and milk yield and composition of dairy cows offered either 5 or 10 kg concentrates/d were evaluated in a ten treatment, partly balanced, changeover design experiment involving 50 cows in early lactation. Concentrates were prepared to provide 0, 150, 300 or 450 g fish oil/cow per d or 300 g fish oil/cow per d from a premix when each animal was offered 5 kg/d. The fish oil was predominantly from herring and mackerel caught in the North Atlantic while the fish oil premix was obtained from a commercial source and used palm kernel expeller as a carrier. Increasing fish oil supplementation decreased silage dry matter intake and the concentrations of milk fat and protein, and increased milk yield and diet digestibility. There were significant interactions between concentrate feed level and level of fish oil for silage intake and milk yield. Other than for the concentrations of milk fat and protein, and 20:4n-6 fatty acids, the source of fish oil did not affect forage intake or animal performance. Fish oil supplementation also decreased the concentrations of milk protein by 0.9 g/kg for each 100 g increase in fish oil supplementation, the depression being similar at each level of concentrate feeding. Supplementing the feed of dairy cows with 450 g fish oil/cow per d decreased the concentration of milk fat by 15 g/kg. This study also showed that feeding dairy cattle with fish oil is an efficient method of increasing eicosapentaenoic acid in the human diet through transfer into milk.     

Physicochemical and sensory properties of milk fortified with iron microcapsules prepared with water‐in‐oil‐in‐water emulsion during storage

This study investigated the possibility of fortifying iron microcapsule powder into milk and the effects of the fortification on the physicochemical and sensory properties of the products during storage. The iron microcapsules were prepared by the water‐in‐oil‐in‐water (W/O/W) emulsion technique. Fortifying the lower concentrations (0.1–0.3%, w/v) of iron microcapsules into the milk samples did not significantly change thiobarbituric acid values. The L‐values for the milk samples were not significantly influenced by fortifying iron microcapsules (0.1–0.7%, w/v). The overall acceptability scores were not affected when the lowest concentration of iron microcapsules (0.1%, w/v) was fortified into the milk.     

Heat-induced aggregation of bovine lactoferrin at neutral pH: Effect of iron saturation

The goal of our study was to characterize the effect of iron saturation on the thermal aggregation of lactoferrin (Lf). Iron saturation markedly increased the thermal stability of Lf and decreased aggregation. Heating holo-Lf at 80 °C led to soluble polymer formation whereas apo and native Lf associated into large insoluble aggregates. The thermal aggregation of holo-Lf was mainly driven by non-covalent interactions, with intermolecular thiol/disulphide reactions also observed above 80 °C. For apo and native Lf, intermolecular thiol/disulphide reactions increased, suggesting that free thiol residues initiated cross-linking reactions and that iron saturation contributed to maintaining Lf disulphide bond integrity and protecting the protein from aggregation. We demonstrated that apo-Lf in the presence of N-ethylmaleimide (NEM) could undergo large aggregate formation through non-covalent interactions without the participation of intermolecular disulphide links. A mechanism for the thermal aggregation of Lf is proposed, emphasizing the influence of iron saturation.