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Highlights • A new alternative to classic fishmeal production is proposed, using the pH shift method. • The pH shift process is proposed as an efficient method of working with high bone-low meat sources, such as fishery byproducts. • Protein yield is affected by the treatment that is applied during the pH shift process. • Proximate composition of the pH shift produced protein concentrates is also subject to treatment. Abstract There is a strong need in animal production for sustainable protein sources used in feed. The aim of the present study was to evaluate the potential of the pH-shift process as a method to concentrate proteins from complex bone-rich herring (Clupea harengus) by-products. By-product parts (frame, head, guts), protein solubilization pH (pH 2.8 or 11.3) and separation g-force (800 or 8000 g) were varied. The findings revealed that protein recovery yields of up to 60% were obtained and that higher protein yield was obtained from the alkaline than the acid process. By-product part and g-force had no significant impact on protein yield. Protein levels reached in the concentrates were 75–80 % (dw basis). Protein concentrates contained a similar amino acid profile as have been reported for fishmeal, with ∼40% essential amino acids and up to 7.8% and 2.8% of lysine and methionine. Residual levels of LC n-3 PUFA as well as calcium, magnesium, potassium and phosphorous were also found in the produced protein concentrates which could be an added value. Acid produced concentrates were particularly high in calcium potassium and phosphorous. Provided a careful evaluation, the pH-shift process could become a successful alternative to classic fish meal production for increasing the use of fish by-products for production of protein ingredients for feed. [ABSTRACT FROM AUTHOR]

Abstract: The growing awareness of the relationship between diet and health has led to an increasing demand for food products that support health above and beyond providing basic nutrition. Probiotics are live organisms present in foods, which yield health benefits related to their interactions with the gastrointestinal tract. Phytases are a subgroup of phosphatases that catalyse the desphosphorylation of phytate, which reduces its negative impact on mineral bioavailability, and generates lower inositol phosphates. The aims of this investigation were to (i) study the ability of the probiotic candidate Bifidobacterium pseudocatenulatum to degrade phytate in synthetic medium, to (ii) identify the lower inositol phosphates generated, to (iii) study its survival under conditions mimicking gastrointestinal passage and finally to (iv) assess adhesion of the bacteria to Caco-2 cells. The first steps of InsP 6 degradation by B. pseudocatenulatum phytate-degrading enzyme/s were preferentially initiated at the DL-6-position and 5-position of the myo-inositol ring. It suggests that the main InsP 6 degradation pathway by B. pseudocatenulatum by sequential removal of phosphate groups was D/L-Ins(1,2,3,4,5)P 5 or D/L-Ins(1,2,3,4,6)P 5; D/L-Ins(1,2,3,4)P 4; to finally Ins(1,2,3)P 3 and D/L-Ins(1,2,4)P 3/D/L-Ins(1,3,4)P 3. This human strain also showed a notable tolerance to bile as well as a selective adhesion capacity (adhesion to control surfaces was zero), to human intestinal Caco-2 cells comparable to the commercial probiotic B. lactis. The phytate-degrading activity constitutes a novel metabolic trait which could contribute to the improvement of mineral absorption in the intestine as a nutritional probiotic feature with potential trophic effect in human gut. [Copyright &y& Elsevier]

The effect of alginate on ileostomy excretion of sterols and nutrients was investigated in six ileostomy subjects fed a constant low-fiber diet with or without supplementation with 7.5 g sodium alginate. A mean of 95% of uronic acids derived from the sodium alginate was recovered in the ileostomy contents. Supplementation with alginate increased fat excretion by 140% and decreased bile acids excretion by 12%. Sodium and potassium excretion were significantly increased whereas starch and nitrogen excretion were unchanged. Five of six subjects showed a decreased apparent absorption of iron and manganese with alginate, which, however, was not statistically significant. Absorption of phosphorus, calcium, magnesium, and zinc were unchanged. Almost no digestion of sodium alginate occurs in the stomach and small intestine. The increased fatty acids excretion may be explained by the binding or trapping of fatty acids in the gel matrix formed by alginate, which may also cause a reduced bile flow. [ABSTRACT FROM AUTHOR]

Structural, functional and nutritional properties of protein recovered from brown seaweed, S. latissima with alkaline solubilization/isoelectric precipitation as a function of different post-harvest stabilization methods were studied. The latter included freezing at −20 °C/-80 °C, oven-drying, sun-drying, freeze-drying and ensilaging. Also, the efficacy of freeze/thaw-aided precipitation (F/T) in improving protein recovery of the process was evaluated. The freeze-dried, oven-dried, and −20 °C frozen seaweeds resulted in significantly higher protein yield than the −80°C-frozen, sun-dried and ensiled biomasses. F/T increased protein precipitation and doubled total protein yield. Sun-drying and −20°C-freezing caused extensive protein degradation as revealed by SDS-PAGE and HP-SEC, while oven-drying altered the seaweed protein structure with less α-helices. Functional properties of the seaweed proteins were remarkably affected by stabilization condition and F/T, but nutritional value of the proteins was only dependent on stabilization method. Thus, to efficiently recover seaweed proteins, its post-harvest stabilization condition must be carefully chosen based on the final application of the proteins. Image 1005 • Protein yield was strongly governed by post-harvest stabilization method. • Freeze/thawing doubled total protein yield of the process. • Functional properties of proteins were remarkably affected by stabilization method. • Structure and molecular weight of proteins were governed by stabilization method. [ABSTRACT FROM AUTHOR]

Abstract: The fermented cereal-based gruel togwa is used as weaning food for children in Tanzania. Togwa is rich in minerals but these are often not available for uptake in the human intestine due to natural inhibitors, such as phytate (IP6). The yeasts Pichia kudriavzevii TY13, Hanseniaspora guilliermondii TY14 and TY20, isolated from Tanzanian togwa, and selected for high phytase activity in complex yeast medium YPD, were now studied regarding their ability to degrade IP6 in maize-based model togwa. A modified constitutively high-phytase producing Saccharomyces cerevisiae BY80 and commercial Aspergillus ficuum phytase were included for comparison. In addition, a strain of Lactobacillus plantarum was included in the model-togwa set-up. All yeasts in the study grew and reached final cell density 1.5–2 log units higher than the start value. S. cerevisiae BY80 degraded 85% of the IP6 in 48h; the same degradation level as with A. ficuum phytase (89%). Of the togwa-isolated yeasts, P. kudriavzevii TY13 and H. guilliermondii TY14 showed strong phytate degradation in the model-togwa; 95% or more of the initial IP6 was degraded after 48h. This corresponds to a remaining level of 0.4 and 0.3μmol IP6/g dw. Co-inoculation with L. plantarum did not increase IP6 degradation. Moreover, fermentation with P. kudriavzevii TY13 yielded a successive increase in inorganic phosphate (Pi), from 0.7 to 5.4mM, suggesting a phytase production in TY13 which is fairly insensitive to Pi repression. The study shows that phytate in a model togwa is available for yeast phytase enzymes, and addresses the importance of strain selection for effectively degrading the phytate. Certain yeasts originating from togwa seem to have developed a natural high phytase production, and P. kudriavzevii TY13 and H. guilliermondii TY14 seem particularly well adapted to phytate degradation in togwa, and is our choice for further studies and strain improvement. [Copyright &y& Elsevier]

The study was conducted to examine if crude enzymes (E) produced from Aspergillus niger by solid state fermentation could bio-transform carbohydrates, proteins, inositol phosphate (InsP) and saponins in soybean meal (SBM) under low moisture conditions. Two experiments were performed to determine the effect of mixing, moisture content, treatment time and E levels during enzyme hydrolysis. 1) A single replicate 2 3 full factorial screening design was used to determine the effect of the independent continuous variables time (30 and 70 min), moisture (350 and 450 g kg −1 DM), and the category variable mixing (i.e. effect of static conditions vs. active mixing (X3, S/M)) during the enzyme hydrolysis. 2) A three factorial central composite design (CCD) was used to study the effects of moisture content (316–484 g kg −1 DM), time of hydrolysis (16.4–83.6 min), and E content (0.32-3.68 g kg −1 SBM dry matter (DM)). The first experiment demonstrated that hydrolysis of InsP 6 was significantly affected by time (P < 0.01), moisture content (P < 0.0001) and static vs. mixing (P < 0.01). The hydrolysis of Bb-DDMP was also significantly affected by static vs. mixing (P < 0.05). The second experiment demonstrated that the hydrolysis of InsP 6 was significantly affected by time (P < 0.001), moisture (P ˂ 0.001) and enzyme content (P ˂ 0.01). The InsP 6 content was reduced 84% after 70 min, at a moisture content of 450 g kg −1 DM with the addition of 3 g enzyme kg −1 SBM DM, the InsP 5 -InsP 3 were not accumulated at these parameter settings. The hydrolysis of the saponin group Bb was explained by the enzyme square regressor (P < 0.001) and the interaction between moisture and enzyme (P < 0.001) reaching a maximum by the addition of 2.5 g enzymes kg −1 SBM DM at 484 g kg −1 moisture content. No significant effects on soluble protein and dietary fiber were observed. Mink were fed three diets containing 50% of the protein from SBM, SBM treated without enzymes or treated with enzymes. There was a trend of improved ash apparent digestibility in mink by the enzyme treatment (P = 0.07), but not for phosphorous. The apparent digestibility of protein and amino acids (AA) in mink was improved by the heat treatment used to inactivate the enzymes (P < 0.001), however, not by the enzyme treatment itself. [ABSTRACT FROM AUTHOR]