Bioactivity of ellagic acid-, lutein- or sesamol-enriched meat patties assessed using an in vitro digestion and Caco-2 cell model system

Interest exists in the manufacture of functional meat products whereby synthetic antioxidants are replaced with naturally-sourced compounds. Therefore the aim of this study was to determine the bioactivity of pork and beef patties containing ellagic acid (600 μg/g), lutein (200 μg/g) or sesamol (500 μg/g). Cooked pork and beef patties were subjected to an in vitro digestion procedure and the resultant micelles were added to human intestinal Caco-2 cells. Supplementation with micelles from lutein-enriched pork patties protected (P < 0.05) against H₂O₂-induced cell injury whereas the presence of control beef, lutein-enriched beef or ellagic acid-enriched beef, at levels ?20% (v/v), enhanced (P < 0.05) oxidant-induced cytotoxicity. None of the pork patties significantly modulated cellular glutathione content. Micelles from all the enriched pork patties significantly protected against H₂O₂-induced DNA damage. In conclusion, the cytoprotective and genoprotective effects of ellagic acid, lutein, and sesamol, when incorporated into meat systems, depend greatly on the food matrix.     

Frozen storage characteristics of low-salt and low-fat beef patties as affected by Wakame addition and replacing pork backfat with olive oil-in-water emulsion

Characteristics of beef patties with low-salt (0.5%) and low-fat (<10%) contents were studied during frozen storage as affected by addition of Wakame seaweed (3%) and partial or total replacement of pork backfat with olive oil-in-water emulsion. Patties with Wakame presented less (P < 0.05) thawing and cooking losses and were softer (P < 0.05) than patties without seaweed. A softening effect (P < 0.05) induced by olive oil emulsion was observed only in seaweed-free patties. Lipid oxidation and microbiological counts in reformulated products were not a limiting factor for frozen stability. Wakame incorporation increased (P < 0.05) mineral contents, but all products presented the same Na/K ratio. Observed changes in microstructure were associated with seaweed addition (formation of alginate chains). All products were judged acceptable by the sensory panel. In the course of frozen storage no important changes were found in the target properties due to the different treatments.     

Thermal inactivation of Bacillus anthracis Sterne in irradiated ground beef heated in a water bath or cooked on commercial grills

The thermal stability of heat-shocked and non-heat-shocked spores of the virulence-attenuated Sterne strain of Bacillus anthracis was evaluated at select temperatures in irradiated, raw ground beef (25% fat) heated in a water bath or cooked using two different commercial grills. For the former, 3-g portions of inoculated ground beef were packaged in bags that were completely immersed in a temperature-controlled circulating water bath held at 65 °C (149 °F), 70 °C (158 °F), 75°(167 °F), and 80 °C (176 °F) for a predetermined length of time. For the latter, formed ground beef patties (95-g each) were inoculated with spore stock A or B of the Sterne strain and then cooked on a commercial open-flame gas grill or on a commercial clamshell electric grill to achieve target internal temperatures of either 71.1 °C (160 °F), 82.2 °C (180 °F), or 93.3 °C (200 °F). Cooking ground beef patties on commercial grills, resulted in reductions of ca. 0.8 to 3.5 log₁₀ CFU/g for spore stocks A and B of B. anthracis Sterne after heating to 71.1 °C (160 °F), 82.2 °C (180 °F), or 93.3 °C (200 °F) on either the open-flame gas grill which required ca. 9.6 min to reach the target internal temperatures or on the clamshell electric grill which required ca. 4.0 min to reach the target internal temperatures. In comparison, our data using a water bath system and heating at 65° to 80 °C predict nearly 4 log reductions in spore levels for short times, ~½ min, depending possibly on the temperature. Thus, our data suggest that models based on heating ground beef in a water bath is not a good predictor of reductions of levels of spores of B. anthracis Sterne strain that would be obtained when cooking ground beef patties on commercial grills under conditions that may be typically used by consumers and/or retail establishments. Nevertheless, our data validated that cooking ground beef patties on a commercial grill at a temperature considered to be “well-done” and a temperature (71.1 °C;160 °F) recommended by the USDA/FSIS, is effective at killing spores of B. anthracis Sterne.Industrial relevanceHeating ground beef in a water bath or cooking ground beef patties on commercial grills under conditions simulating those that are used by consumers and/or that occur in retail food service establishments is effective at killing spores of B. anthracis Sterne.     

Assessment of conventional and microwave heating induced degradation of carotenoids in olive oil by VIS Raman spectroscopy and classical methods

Raman spectroscopy, as a fast non-destructive method, has shown its potential in revealing heat-induced degradation of extra virgin olive oil carotenoids during microwave versus conventional heating processes. A progressive degradation in carotenoids was observed, starting at 180 °C and 140 °C in microwave and conventional heating processes respectively; this was followed by a rapid degradation at 180 °C only with conventional heating. As the main difference, the Raman bands due to carotenoids completely disappeared at 203 °C with conventional heating, while these bands could still be observed even up to 225 °C with microwave heating. Furthermore a loss of cis double bonds and slightly changes in free fatty acid was also observed in both heating processes. A precise calibration model was established using partial least squares regression, which can be used for monitoring carotenoids content degradation during heating. The accuracy of the model was estimated using the root mean square errors and the correlation coefficient.     

Oxidative stability of virgin olive oil enriched with carnosic acid

The aim of this study was to evaluate the effect of the addition of carnosic acid on the oxidative stability of virgin olive oil. Two different amounts of carnosic acid (0.01 and 0.1 g/100 g oil) and two different temperatures (accelerated aging temperature, 60 °C; deep frying temperature, 180 °C) were considered. The influence of carnosic acid and heating time on the stability of the oils was studied by experimental design. The results obtained at 60 °C showed a dose dependent inhibition in the formation of primary and secondary oxidation products and a dose dependent enhancement of radical scavenging activity, which was only less significantly influenced by heating time. On the contrary, at 180 °C no protective effect against lipid oxidation was observed and the radical scavenging activity was practically zeroed by heating, probably as a consequence of a fast decomposition of carnosic acid.     

Determination of cholesterol oxidation products in raw and processed beef and pork preparations

The effect of pan-frying on the formation of cholesterol oxidation products (COPs) in different processed meat samples (beef patties, braised meat, and fillets of pork) was studied. Samples were pan-fried with or without addition of oil. Different unsaturated oils (olive oil, corn oil or partly hydrogenated plant oil) were used throughout the study. After extraction, seven toxicologically relevant COPs were analyzed using LC–MS. Prior to heat processing up to 6.7 mg COPs/kg extracted fat could be detected in the raw material. Neither the cholestanetriol nor 25-hydroxycholesterol, which are the most cytotoxic COPs in vitro, were detectable in any sample. Differences in the COPs contents were observed between beef (up to 16.5 mg/kg extracted fat) and pork (up to 22.2 mg/kg extracted fat) samples. In prepared samples higher COPs content was noted compared with raw samples. Generally, a certain order of COPs increase dependent on the plant oil used could be recognized: corn oil < partially hydrogenated plant oil < olive oil. It appears that short heating time, mild heating conditions, and the use of fresh and shortly stored raw materials keep COPs levels low.     

Ascorbate,green tea and grape seed extracts increase the shelf life of low sulphite beef patties

Green tea (GTE) and grape seed (GSE) extracts are proposed as preservatives for increasing the shelf life of low sulphite raw beef patties. The antioxidant and antimicrobial activities of both extracts were compared with ascorbate. Five groups were established for the patties: Control (with no additives), S (100 SO₂), SA (100 SO₂ + 400 sodium ascorbate), ST (100 SO₂ + 300 GTE) and SG (100 SO₂ + 300 GSE) (mg per kg of meat). Patties were stored at 4 °C in aerobic packaging for 0, 3, 6 or 9 days under retail display conditions. Meat spoilage (total viable and coliform counts, pH, lightness, chroma, hue angle, metmyoglobin and TBARS) was determined. The sensory contribution of the extracts to cooked patties was evaluated (colour, odour, flavour and texture). The results pointed to the possibility of using low SO₂-vegetable extract combinations to preserve raw meat products. ST, SG and SA delayed microbial spoilage, redness loss and lipid oxidation, thus increasing the shelf life of the raw sulphite beef patties by 3 days. ST, SG and SA also delayed the onset of rancid flavours in cooked patties. No anomalous sensory traits were caused by either extract. Ascorbate, GTE and GSE improved the preservative effects of SO₂ on beef patties, especially against meat oxidation. This suggested that the quantity of SO₂ added can be reduced to obtain healthier raw meat products.     

Physicochemical and organoleptic characteristics of seasoned beef patties with added glutinous rice flour

This study was conducted to determine if glutinous rice flour (GRF) could be a functional food additive to potentially replace corn starch (CS), soy protein isolate (SPI) and/or sodium tripolyphosphate (STPP) to improve the physicochemical and organoleptic characteristics of seasoned beef patties. GRF had a lower cook loss among the treatment groups due to an increase in fat and moisture retentions (p < 0.05). GRF lowered texture profile values for hardness, gumminess, springiness, and chewiness (p < 0.05) of the patties, which are generally beneficial for this product. The beef patties with GRF were juicier and more tender than the control and other treatments (p < 0.05). Hedonic scores for juiciness, tenderness and overall acceptability were the highest for the beef patties with 1 and 3% GRFs, suggesting that GRF may be an effective functional ingredient to improve the textural quality of seasoned beef patties.     

Packaging-specific influence of chitosan on color stability and lipid oxidation in refrigerated ground beef

We examined the influence of chitosan on lipid oxidation and color stability of ground beef stored in different modified atmosphere packaging (MAP) systems. Ground beef patties with chitosan (1%) or without chitosan (control) were packaged either in high-oxygen MAP (HIOX; 80% O₂ + 20% CO₂), carbon monoxide MAP (CO; 0.4% CO + 19.6% CO₂ + 80% N₂), vacuum (VP), or aerobic packaging (PVC) and stored at 1 °C. Chitosan increased (P < 0.05) redness of patties stored in PVC and CO, whereas it had no effect (P > 0.05) in HIOX. Chitosan patties demonstrated lower (P < 0.05) lipid oxidation than controls in all packaging. Control patties in PVC and HIOX exhibited greater (P < 0.05) lipid oxidation than those in VP and CO, whereas chitosan patties in different packaging systems were not different (P > 0.05) from each other. Our findings suggested that antioxidant effects of chitosan on ground beef are packaging-specific.     

Influence of emulsifier type on in vitro digestibility of lipid droplets by pancreatic lipase

The objective of this study was to investigate the influence of interfacial composition on the in vitro digestion of emulsified lipids coated by various emulsifiers by pancreatic lipase. Sodium caseinate, whey protein isolate (WPI), lecithin and Tween 20 were used to prepare corn oil-in-water emulsions (3 wt% oil). Pancreatic lipase (1.6 mg/mL) and/or bile extract (5.0 mg/mL) were added to each emulsion and the particle charge, droplet aggregation, microstructure and free fatty acids released were measured. In the absence of bile extract, the amount of free fatty acids released per unit volume of emulsion was much lower for lipid droplets coated by Tween 20 (13 ± 16 μmol ml⁻¹) than those coated by lecithin (75 ± 20 μmol ml⁻¹), sodium caseinate (220 ± 24 μmol ml⁻¹) or WPI (212 ± 6 μmol ml⁻¹). In the presence of bile extract, there was an appreciable increase in the amount of free fatty acids released in all the emulsions, with the most appreciable effects being observed in the Tween 20-stabilized emulsions. The stability of the emulsions to droplet flocculation and coalescence during hydrolysis was also strongly dependent on emulsifier type, with the WPI emulsions being the least stable and the Tween 20 emulsions being the most stable. Our results suggest that the access of pancreatic lipase to emulsified fats decreases in the following order: proteins (caseinate and WPI) > phospholipids (lecithin) > non-ionic surfactants (Tween 20). These results may have important consequences for the design of foods with either increased or decreased lipid bioavailability.     

Interfacial characteristics and microchannel emulsification of oleuropein-containing triglyceride oil–water systems

This study investigated the adsorption characteristics of olive leaf water extract and its major phenolic compound, oleuropein, at the triglyceride oil–water interface. We also investigated the preparation characteristics of food-grade triglyceride oil-in-water (O/W) emulsions stabilized by oleuropein using microchannel (MC) emulsification. Refined soybean oil, extra virgin olive oil, refined olive oil, and medium-chain triacylglyceride (MCT) oil were used as triglyceride oils. Both olive leaf extract (OLE) and highly purified oleuropein had a pronounced ability to decrease the interfacial tension at the refined soybean oil–water interface. The packing of oleuropein molecules at the triglyceride oil–water interface was estimated on the basis of their surface excess concentration and area occupied per molecule, determined from the Gibbs adsorption equation. MC emulsification was performed using a silicon grooved MC array plate (model CMS6-2). The continuous aqueous phase contained 0.6 wt.% of oleuropein. Monodisperse, oleuropein-stabilized O/W emulsions with an average droplet diameter of 25 μm and coefficient of variation (CV) of < 5% were produced in all systems, except the MCT oil-containing system, even in the absence of a cross-flowing continuous phase. This successful MC emulsification was observed without droplet coalescence for 15 h of continuous operation. Our findings demonstrate that the use of oleuropein, which has an interfacial activity, is capable of producing monodisperse O/W emulsions using MC emulsification and stabilizing the generated oil droplets when appropriate types of triglyceride oils are used.     

Deterioration of olive,corn and soybean oils due to air,light, heat and deep-frying

To follow the relative rate of oxidative deterioration of edible oils, refined olive, corn and soybean oils were analyzed periodically for their peroxide value (PV), p-anisidine value (p-AV) and iodine value (IV) following exposure to air and air–light for 30 days. Changes in the above values of the oils were also examined and after being used for deep frying of French fries at 180 °C for varying periods of time i.e. 30, 60 and 90 min PV and p-AV values increased in the order, deep frying > air–light exposure > air exposure, while the values with respect to the oils increased as soybean > corn > olive. Decreases in IV followed the same pattern, i.e. deep frying > air–light > air and soybean > corn > olive. %Free fatty acid increased with increase in time of deep-frying. Deep-frying of French fries in corn oil was also carried out in presence of caffeic, ferulic, vanillic acid and crude tea extract as antioxidants. All antioxidants effectively reduced the oxidation rate in the oil as detected by decreases in PVs and p-AVs and relatively low reduction rates in IVs for all the frying times. The order of antioxidative activity was caffeic acid > vanillic acid > ferulic acid > tea extract. Variation in %FFA of corn oil due to variation in nature of fried food was also analyzed. %FFA of the oil used for deep frying of chicken drum sticks were higher than the values of the oil used for deep-frying of French fries.     

Cow biological type affects ground beef colour stability

To determine the effects of cow biological type on colour stability of ground beef, M. semimembranosus from beef-type (BSM) and dairy-type (DSM) cows was obtained 5 d postmortem. Three blends (100% BSM, 50% BSM + 50% DSM, 100% DSM) were adjusted to 90% and 80% lean points using either young beef trim (YBT) or beef cow trim (BCT), then packaged in high oxygen (High-O₂; 80% O₂) modified atmosphere (MAP). The BSM + YBT patties had the brightest colour initially, but discoloured rapidly. Although DSM + BCT patties had the darkest colour initially, they discoloured least during display. Metmyoglobin reducing ability of ground DSM was up to fivefold greater than ground BSM, and TBARS values of BSM was twofold greater than DSM by the end of display (4 d). Though initially darker than beef cow lean, dairy cow lean has a longer display colour life and may be advantageous to retailers using High-O₂ MAP.     

Physical characteristics of submicron emulsions upon partial displacement of whey protein by a small molecular weight surfactant and pectin addition

O/W emulsions (6 wt.% olive oil) were prepared at pH 3.3 using different WPI:Tween 20 weight ratios (1:0, 3:1, 1:1, 1:3, 0:1) at 1 wt.% total concentration. The emulsion droplet size was found to decrease with an increase in Tween 20. A minimum droplet size of d_3,2 300 nm was found for Tween systems alone, similar to that found (360 nm) for a 1:1 WPI:Tween 20 combination (p < 0.05). This specific composition showed a value for the interfacial tension close to that of Tween 20 alone. However, the emulsions presented low stability regardless of the WPI:Tween 20 ratio. To increase their stability, pectin was added, in various concentrations (0.2, 0.4 and 0.6 wt.%), using the Layer by Layer technique. In the presence of pectin, the ζ-potential of the oil droplets became negative; indicating that negatively charged pectin was absorbed onto the positively-charged droplet surface forming a secondary layer. The additional layer resulted in a wide range of emulsion stability. For all pectin concentrations, the 1:1 ratio of WPI:Tween 20 showed the highest stability. In most emulsions, extensive aggregation of oil droplets was observed, and their viscosity increased. Insufficient amounts of pectin to form the secondary layers led to bridging flocculation phenomena of oppositely charged pectin and proteins, leading to aggregation of the oil droplets. The higher the concentration of pectin, the greater the stability of the emulsion due to higher viscosity. All in all, the addition of a second layer consisting of pectin can be used to increase the stability of an emulsion containing emulsion droplets in the sub-micron range.     

Pomegranate husk extract,punicalagin and ellagic acid inhibit fatty acid synthase and adipogenesis of 3T3-L1 adipocyte

Fatty acid synthase (FAS) has been recognized as a potential therapeutic target for obesity. In this study, for the first time, the inhibitory effect of pomegranate husk extract, punicalagin and ellagic acid on FAS was investigated. We found them potently inhibiting the activity of FAS with half-inhibitory concentration values (IC₅₀) of 4.1 μg/ml (pomegranate husk extract), 4.2 μg/ml (4.50 μM, punicalagin) and 1.31 μg/ml (4.34 μM, ellagic acid), respectively. Moreover, they all exhibited time-dependent inactivation of FAS. Punicalagin and ellagic acid inhibited FAS with different mechanisms compared to previously reported inhibitors, through inactivating acetyl/malonyl transferase and β-ketoacyl synthase domains, respectively. Additionally, 100 μg/ml pomegranate husk extract, 5.24 μg/ml (5 μM) punicalagin and 4.5 μg/ml (15 μM) ellagic acid effectively reduced lipid accumulation inside FAS over-expressed 3T3-L1 adipocytes. Since FAS plays a key role in the biosynthesis pathway of fatty acid, these findings suggest that pomegranate husk extract, punicalagin and ellagic acid have potential in the prevention and treatment of obesity.     

Effects of reducing agents on premature browning in ground beef

This study was performed to investigate the effects of food-grade reducing agents on counteracting premature browning (PMB) and to determine the relative heat stability of different redox states of bovine myoglobin (Mb). Sodium erythorbate (SE), erythorbic acid (EA), sodium ascorbate (SA), ascorbic acid (AA) and ascorbyl palmitate (AP) were added to ground beef (15% fat) at a concentration of 2.3 mM; patties were prepared and stored at 4 °C and at −18 °C. Surface redness (a* values), lipid oxidation and total reducing activity (TRA) were measured on raw beef, and a* values recorded from cooked internal surfaces. Bovine Mb was purified from biceps femoris muscle and heat capacity was measured using differential scanning calorimetry. All reducing agents decreased lipid oxidation and increased TRA relative to controls (p < 0.05). In general, SE and SA were more effective at maintaining red color in cooked ground beef patties than other reducing agents (p < 0.05). The temperature at peak heat capacity, T_m, of metmyoglobin appeared lower than that of oxymyoglobin and deoxymyoglobin. Reducing agents can maintain Mb in the reduced state, and their addition to ground beef may be one method of preventing PMB.     

Cyanidin-3-glucoside,nutritionally important constituents and in vitro antioxidant activities of Santalum album L. berries

Anthocyanins are ubiquitous plant pigments. They are hydrophilic, and have high tinctorial value hence, used as natural food colorant. The main aim of this study was characterization of Santalum album L. berries for its pigment content, nutritionally important phytoconstituents and functional attributes. Major pigment identified was cyanidin-3-glucoside (0.21% FW) as confirmed by spectral characteristics including LC–MS. Nutrients such as total carbohydrates (8.5), proteins (5.8), free amino acids (0.8 g), oil (1.5 g), ascorbic acid (1.5 μg), tocopherols (0.3 mg) and niacin (5.2 mg) per 100 g berries were determined along with total soluble solids (13.4°Brix) and phenols (3.1 mg GAE/g). Reducing power and DPPH· scavenging assays showed highest activity in methanol extract, which also efficiently protected bleaching of β-carotene (EC₅₀ 285 μg/mL) in β-carotene–linoleate model. Pigment rich crude extract was not toxic to HepG2 cells during 24 h exposure, whereas cyanidin-3-glucoside was cytotoxic (IC₅₀ 0.1 μg/mL).     

Production of sophorolipids by the yeast Candida bombicola using simple and low cost fermentative media

In the present study, low cost media based on sugarcane molasses and three different oils, viz. soybean oil, sunflower oil or olive oil, were evaluated for the production of sophorolipids (SLs) from the yeast Candida bombicola in batch shake flasks. At the end of 5 days fermentation period, medium containing only molasses and soybean oil gave a maximum SLs yield of 23.25 ± 1.07 g/l compared to other media containing sugarcane molasses and either sunflower oil or olive oil. Moreover, the obtained yield was comparable to that obtained using a conventional synthetic medium having yeast extract, urea, soybean oil and glucose. Emulsification activity and stability of the produced SLs using different oils, and the effect of pH and temperature on the same were also studied. And these properties of the biosurfactant indicated good potential of the cheaply produced SLs in the pretreatment of high fats and oils containing food industry wastewaters.     

The increased viability of probiotic Lactobacillus salivarius NRRL B-30514 encapsulated in emulsions with multiple lipid-protein-pectin layers

Probiotics have demonstrated various health benefits but have poor stability to sustain food processing and storage conditions, as well as after ingestion. Biopolymer beads are commonly studied to encapsulate probiotic cells to improve their stability, but the millimeter-dimension of these beads may not meet the quality requirement of food products. The aim of this study was to enhance the viability of Lactobacillus salivarius NRRL B-30514 by encapsulation in emulsion droplets with multiple lipid-protein-pectin layers. Spray-dried L. salivarius was suspended in melted anhydrous milk fat that was then emulsified in a neutral aqueous phase with whey protein isolate or sodium caseinate to prepare primary solid/oil/water (S/O/W) emulsions. Subsequently, pectin was electrostatically deposited onto the droplet surface at pH 3.0 to form secondary emulsions. The encapsulation efficiency was up to 90%. After 20-day storage at 4 °C, the viable cell counts of bacteria in secondary emulsions at pH 3.0 and primary emulsions at 7.0 were 3 log higher than the respective free cell controls. After heating at 63 °C for 30 min, free L. salivarius was inactivated to be undetectable, while about 2.0 log CFU/mL was observed for primary (at pH 7.0) and secondary (at pH 3.0) emulsion treatments. Additionally, a 5 log-CFU/g-powder reduction was observed after spray drying free L. salivarius, while a 2 log CFU/g reduction was observed for emulsion treatments with capsules smaller than 20 μm. Furthermore, cross-linking the secondary emulsion with calcium enhanced the viability of L. salivarius after the simulated gastric and intestinal digestions. Therefore, the studied S/O/W emulsion systems may be used to improve the viability of probiotics during processing, storage, and gastrointestinal digestion.     

Physical stability of emulsion encapsulated in alginate microgel particles by the impinging aerosol technique

Emulsion filled alginate microgel particles can be applied as carrier systems for lipophilic actives in pharmaceutical and food formulations. In this study, the effects of oil concentration, emulsifier type and oil droplet size on the physical stability of emulsions encapsulated in calcium alginate microgel particles (20–80 μm) produced by a continuous impinging aerosol technique were studied. Oil emulsions emulsified by using either sodium caseinate (SCN) or Tween 80 were encapsulated at different oil concentrations (32.55, 66.66 and 76.68% w/w of total solids content). The emulsions were analysed before and after encapsulation for changes in emulsion size distribution during storage, and compared to unencapsulated emulsions. The size distribution of encapsulated fine emulsion (mean size ~ 0.20 μm) shifted to a larger size distribution range during encapsulation possibly due to the contraction effect of the microgel particles. Coarse emulsion droplets (mean size ~ 18 μm) underwent a size reduction during encapsulation due to the shearing effect of the atomizing nozzle. However, no further size changes in the encapsulated emulsion were detected over four weeks. The type of emulsifier used and emulsion concentration did not significantly affect the emulsion stability. The results suggest that the rigid gel matrix is an effective method for stabilising lipid emulsions and can be used as a carrier for functional ingredients.