Influence of Homogenization Time and Speed on Rheological and Volatile Composition in Olive-Based Pâtés

The influence of the homogenization time and speed on rheological and volatile composition in olive-based pâtés was studied. Five experimental trials were performed applying different combinations of time and speed homogenization: 1, 3, and 5 min at 12,000 rpm and 4000, 8000, and 12,000 rpm at 5 min. The obtained results showed that the processing parameters of the homogenization step significantly influenced the rheological and sensory properties of olive-based pâtés. Both time and speed influenced the rheological properties of the product. The increase of homogenization time and speed determined a significant reduction of hardness and syneresis. As regards color indices, significantly higher L* values were obtained when intermediate time and speed conditions were applied, whereas a* and b* indices showed a not univocal behavior. Both time and speed variables also influenced the volatile fraction of the pâtés (higher homogenization speed and time corresponded to higher terpenes and aldehydes).

Preparation of Liposomes Containing Oleanolic Acid via Micelle-to-Vesicle Transition

Micelle-to-vesicle transition method was used to make liposomes containing oleanolic acid. First, the solubilization of potassium salt of oleanolic acid at basic condition by micelle formation was confirmed. Using the soluble state of oleanolic acid at basic condition, liposomes containing oleanolic acid was prepared by adjusting pH. After making homogeneous aqueous mixture of potassium salt of oleanolic acid and lecithin in basic condition, the solution was neutralized to produce the lecithinbased liposomes that contain oleanolic acid inside the lipid bilayers. The optimal loading of oleanolic acid to lecithin (about 25 mole%) was found to exist to produce liposomal suspension of small size without homogenization step. Electron microscopy and dynamic light scattering studies showed that the narrowly distributed, reconstituted oleanolic acid-containing liposomes were prepared without severe mechanical treatment.

Chemical and sensory analysis of strawberry flavoured yogurt supplemented with an algae oil emulsion

A yogurt mix (2 g fat and 17 g solids/100 g) was supplemented with an algae oil emulsion to provide 500 mg ω-3 fatty acids per 272 g serving of yogurt white mass. The emulsion was added to the yogurt mix either before or after the homogenization step and prior to pasteurization. It was then flavoured with a strawberry fruit base and fermented and stored for up to three weeks. The oxidative deterioration of the products was determined by hydroperoxide measurements and by trained and consumer sensory evaluations. The hydroperoxide content of the supplemented yogurts increased over the storage treatment and was unaffected by the stage of addition. The trained panel could distinguish a stronger fishy flavour in both of the supplemented yogurts after 22 days storage, but the consumer panel rated both control and supplemented samples similarly, as ‘moderately liked’.

Effect of Homogenization as Pretreatment for the Improvement of Autolysis Efficiency of Kluyveromyces fragilis

A yeast autolysis modified process consisting of a previous homogenization step at 52 MPa ( N= 2) with pH adjustment at 9.5 is developed. The process carried out in 16 h reached a total biomass solubilization around 85%. Autolysis course was not affected by yeast concentration in the studied range (60–140 mg/mL). Initial NaCl concentration of 1% led to a reduced content of this salt in final extract of about 7%, under optimum conditions, in good agreement with current requirements of the food industry. The high levels of biomass solubilization in this process allowed a yield increase of extract from 0.13 kg per liter of yeast suspension (150 mg/mL) in untreated cells to 0.15 kg/L in homogenized cells.

Electrophoretic separation and quantitation of cardiac myosin heavy chain isoforms in eight mammalian species

A protocol for sample preparation and gel electrophoresis is described that reliably results in the separation of the α- and β-isoforms of cardiac myosin heavy chain (MHC-α and MHC-β) in eight mammalian species. The protocol is based on a simple, nongradient denaturing gel. The magnitude of separation of MHC-α and MHC-β achieved with this protocol is sufficient for quantitative determination of the relative amounts of these two isoforms in mouse, rat, guinea pig, rabbit, canine, pig, baboon, and human myocardial samples. The sensitivity of the protocol is sufficient for the detection of MHC isoforms in samples at least as small as 1 μg. The glycerol concentration in the separating gel is an important factor for successfully separating MHC-α and MHC-β in myocardial samples from different species. The effect of sample load on MHC-α and MHC-β band resolution is illustrated. The results also indicate that inclusion of a homogenization step during sample preparation increases the amount of MHC detected on the gel for cardiac samples to a much greater extent than for skeletal muscle samples. Although the protocol described in this study is excellent for analyzing cardiac samples, it should be noted that the same protocol is not optimal for separating MHC isoforms expressed in skeletal muscle, as is illustrated.

A Comparison of Methods for the Isolation of a Wide Range of Viruses from Shellfish

Four methods were compared for the isolation of a wide range of enteric viruses from shellfish. The comparison was aimed at finding a practical and sensitive method to be used routinely. Three of the methods (A, B and C) were based on viral adsorption and desorption using buffers at different pH values. A fourth method (D) consisted of a single homogenization step with no pH adjustments. High recoveries for polio 1 were shown with the first three methods A-C, namely 81%, 79% and 77% respectively. Recoveries for reo 1 (Lang strain) and the simian rotavirus SA11 were not satisfactory using methods A-C. By contrast, method D gave high recoveries for reo and SA11 virus (31% and 68%, respectively). A modified method D generally yielded higher recoveries as indicated by a 91%, 33% and 35% recovery for polio 1, reo and SA11 viruses respectively. Comparison of method A and modified method D for the detection of viruses from environmental shellfish samples indicated that the two methods were of equal sensitivity.

The effect of purification on the ultrastructure and infectivity of egg-attenuated Chlamydia psittaci (6BC)

A procedure is described for the purification of mixed populations of the three different morphological forms of Chlamydia psittaci (6BC) from infected yolk sac membranes. Elementary bodies and small intermediate bodies are not perceptibly damaged during purification which involves homogenization of the host cells, differential centrifugation, sedimentation through 20% sucrose, and treatment with trypsin. The observation that elementary bodies undergo plasmolysis in 20% sucrose is interpreted as indicating that the cytoplasmic membrane of these particles is intact at that stage in the purification. Reticulate bodies and large intermediate bodies are damaged, to a degree, by the homogenization step. This damage takes the form of discontinuities of the outer envelope membrane, and results in the loss of the regular coccobacillary shape of these particles and in an increase in their size. Treatment with a combination of RNase and DNase was found to cause profound damage to all three morphological forms of the chlamydiae.