Olli Tossavainen

α-Lactorphin lowers blood pressure measured by radiotelemetry in normotensive and spontaneously hypertensive rats

Abstract Cardiovascular effects of subcutaneous administration of synthetic α-lactorphin, a tetrapeptide (Tyr-Gly-Leu-Phe) originally derived from milk α-lactalbumin, were studied in conscious spontaneously hypertensive rats (SHR) and in normotensive Wistar Kyoto rats (WKY) with continuous radiotelemetric monitoring. α-Lactorphin dose-dependently lowered blood pressure (BP) without affecting heart rate in SHR and WKY. The lowest dose which reduced BP was 10 μg/kg, and the maximal reductions in systolic and diastolic BP (by 23 ± 4 and 17 ± 4 mm Hg, respectively) were observed at 100 μg/kg dose in SHR. No further reductions were obtained at a higher dose of 1 mg/kg. There were no significant differences in the BP responses to α-lactorphin between SHR and WKY. Naloxone (1 and 3 mg/kg s.c.), a specific opioid receptor antagonist, abolished the α-lactorphin-induced reduction in BP and reversed it into a pressor response, which provides evidence for an involvement of opioid receptors in the depressor action of the tetrapeptide.

Purification and regeneration of diluted caustic and acidic washing solutions by membrane filtration

Abstract The aim of the work was to purify diluted caustic and acidic streams from dairy cleaning-in-place processes (CIP). Nanofiltration of diluted dairy washing solutions, i.e. sodium hydroxide and nitric acid solutions, was studied with spiral wound modules. In addition, re-concentration of purified caustic and acidic washing solutions by reverse osmosis was studied. Nanofiltration reduced the COD content of the caustic washing solution by 76–90% depending on the concentration ratio used. The alkaline/acid content of the nanofiltration permeate was similar to the feed. By reverse osmosis treatment alkaline NF permeates were concentrated from 0.2 to 0.7% NaOH. Concentration of nitric acid did not succeed. The membranes retained their initial pure water fluxes when treated with the conventional CIP procedure after the filtration run.

Effect of milk protein products on the stability of a model low-fat spread

Abstract The surface activity and viscous properties of Na-caseinate, WPC-50, WPI (Albuvir), MPC-65 and gelatine were measured. The proteins were then assessed in a model low-fat spread. At low concentrations, none of these proteins alone produced stable spreads. When the protein concentration in the aqueous phase was increased, the stability of the spread improved. A protein content of 11.7% or higher in the aqueous phase was required to produce a stable spread using Na-caseinate. Alone, only Na-caseinate gave well-structured spreads. The addition of NaCl to the Na-caseinate solution increased the stability of the spread. This was associated with an increase in the apparent viscosity ( η app. ) of the aqueous phase. The stability of the spreads was more dependent on η app. of the aqueous phase at 5 °C and the protein solubility than on the surface activity of the proteins. When combinations of proteins were used, Na-caseinate +MPC-65 (3:1) gave the most satisfactory spread at a total protein concentration of 11.7% in the aqueous phase. A high η app. of the aqueous phase at 5 °C (>1.7 Pa s) and a high protein solubility (>74%) were necessary to produce stable w/o-spreads without water release. Among the milk proteins studied, this requirement was met only by Na-caseinate and Na-caseinate +MPC-65-combinations.

Enzymatic synthesis of fucose-containing galacto-oligosaccharides using β-galactosidase and identification of novel disaccharide structures

Fucosylated oligosaccharides have an important role in maintaining a healthy immune system and homeostatic gut microflora. This study employed a commercial β-galactosidase in the production of fucose-containing galacto-oligosaccharides (fGOS) from lactose and fucose. The production was optimized using experiment design and optimal conditions for a batch production in 3-liter scale. The reaction product was analyzed and the produced galactose-fucose disaccharides were purified. The structures of these disaccharides were determined using NMR and it was verified that one major product with the structure Galβ1–3Fuc and two minor products with the structures Galβ1–4Fuc and Galβ1–2Fuc were formed. Additionally, the product composition was defined in more detail using several different analytical methods. It was concluded that the final product contained 42% total monosaccharides, 40% disaccharides and 18% of larger oligosaccharides. 290 μmol of fGOS was produced per gram of reaction mixture and 37% of the added fucose was bound to fGOS. The fraction of fGOS from total oligosaccharides was determined as 44%. This fGOS product could be used as a new putative route to deliver fucose to the intestine.

Mild protein hydrolysation of lactose-free milk further reduces milk-related gastrointestinal symptoms.

Gastrointestinal symptoms associated with milk are common. Besides lactose, milk proteins may cause symptoms in sensitive individuals. We have developed a method for mild enzymatic hydrolysation of milk proteins and studied the effects of hydrolysed milk on gastrointestinal symptoms in adults with a self-diagnosed sensitive stomach. In a double blind, randomised placebo-controlled study, 97 subjects consumed protein-hydrolysed lactose-free milk or commercially available lactose-free milk for 10 d. Frequency of gastrointestinal symptoms during the study period was reported and a symptom score was calculated. Rumbling and flatulence decreased significantly in the hydrolysed milk group (P < 0·05). Also, the total symptom score was lower in subjects who consumed hydrolysed milk (P < 0·05). No difference between groups was seen in abdominal pain (P = 0·47) or bloating (P = 0·076). The results suggest that mild enzymatic protein hydrolysation may decrease gastrointestinal symptoms in adults with a sensitive stomach.