Quality of Protein Isolates and Hydrolysates from Baltic Herring (Clupea harengus membras) and Roach (Rutilus rutilus) Produced by pH-Shift Processes and Enzymatic Hydrolysis.

Fractionation is a potential way to valorize under-utilized fishes, but the quality of the resulting fractions is crucial in terms of their applicability. The aim of this work was to study the quality of protein isolates and hydrolysates extracted from roach (Rutilus rutilus) and Baltic herring (Clupea harengus membras) using either pH shift or enzymatic hydrolysis. The amino acid composition of protein isolates and hydrolysates mostly complied with the nutritional requirements for adults, but protein isolates produced using pH shift showed higher essential to non-essential amino acid ratios compared with enzymatically produced hydrolysates, 0.84-0.85 vs. 0.65-0.70, respectively. Enzymatically produced protein hydrolysates had a lower total lipid content, lower proportion of phospholipids, and exhibited lower degrees of protein and lipid oxidation compared with pH-shift-produced isolates. These findings suggest enzymatic hydrolysis to be more promising from a lipid oxidation perspective while the pH-shift method ranked higher from a nutrient perspective. However, due to the different applications of protein isolates and hydrolysates produced using pH shift or enzymatic hydrolysis, respectively, the further optimization of both studied methods is recommended.

Effect of supercritical CO2 plant extract and berry press cakes on stability and consumer acceptance of frozen Baltic herring (Clupea harengus membras) mince.

A promising way of processing Baltic herring, Clupea harengus membras, is turning the fish into boneless mince. However, Baltic herring is prone to lipid oxidation, which possesses a challenge for industrial applications. The aim of this work was to study the efficacy of press cakes from Finnish berries and a supercritical CO2 plant extract to limit lipid oxidation during frozen storage of Baltic herring mince and to determine the impact of these additions on consumer acceptance in a fish product. Peroxide value, formation of volatile oxidation products and loss of polyunsaturated fatty acids showed that the tested natural additives decreased oxidation to a greater or similar extent as conventional antioxidants during 10-month storage. While potential of berry press cakes and plant extracts as "green label antioxidants" was shown, consumer study indicated need for further research to reach both optimal antioxidative efficacy and sensory properties.

Black currant seed oil supplementation of mothers enhances IFN-γ and suppresses IL-4 production in breast milk.

BACKGROUND: The first year of infancy is crucial for the development of atopic immune response. Inadequate early Th1 and Treg responses and increased production of Th2 cytokines are associated with atopy. Breast milk contains several immunomodulatory cytokines and other factors that might influence the maturation of the infant's immune system. We assessed the cytokines in breast milk of mother of newborn infants and their associations with black currant seed oil (BCSO) supplementation during pregnancy, mother's atopic status and the development of infant's atopic dermatitis. METHODS: Mothers and infants from an intervention study by black currant seed oil (n = 31) or olive oil as placebo (n = 30) were included in the study. Breast milk samples were collected during the first 3 months of breastfeeding. Breast milk levels of IL-4, IL-5, IL-10, IL-12, IFN-γ and TNF were measured by Luminex technology. RESULTS: BCSO intervention group had decreased level of IL-4 (p = 0.044) and elevated level of IFN-γ (p = 0.014) in breast milk as compared to olive oil group. No significant differences were observed in IL-5, IL-10, IL-12 and TNF levels between the BCSO and olive oil groups. Mothers who had atopic dermatitis had significantly decreased levels of IL-10 (p = 0.044) in breast milk. Breast milk of the mothers of the children who developed atopic dermatitis had lower levels of IFN-γ (p = 0.039) as compared to the breast milk of the mothers of the children without dermatitis. CONCLUSION: Dietary intervention with BCSO had immunomodulatory effects on breast milk cytokine production towards Th2 to Th1 immunodeviation.

[New methods for dietary counselling in Finland]. / Ravitsemusohjauksessa on huomioitava muutakin kuin suositukset.

The observed poor adherence to dietary guidelines is in contrast with their relatively well-known content. Emphasis in psychosocial factors that enhance motivation and self-reliance on dietary counselling could improve the situation. In Finland, three new counselling methods have recently become available. "Neuvokas" is a tool for maternity clinics, enabling easy follow-up of family health behaviour. "Painokas" is a tool-kit that helps in broaching the subject of family health behaviour and resources and motivation. In "Taste School", children are offered food-derived stimulus for their senses. With these new tools, the emphasis on counselling is changed from sharing information to the self-reliant use of information. Families need empowering support and inspiring experiences of healthy food. One's diet is not chosen, it is learned during childhood.

Effects of latitude and weather conditions on contents of sugars, fruit acids, and ascorbic acid in black currant (Ribes nigrum L.) juice.

The genetic background determined the composition of black currants and the compositional response to weather conditions. The variety Melalahti had higher values for glucose and sugar/acid ratio and lower contents of fructose, citric acid, quinic acid, and vitamin C than the varieties Mortti and Ola (p<0.05). In comparison to black currants grown in northern Finland (latitude 66 degrees 34' N), the berries grown in southern Finland (latitude 60 degrees 23' N) had higher contents of fructose, glucose, sucrose, and citric acid (by 8.8, 6.1, 10.0, and 11.7%, respectively) and lower contents of malic acid, quinic acid, and vitamin C (by 31.1, 23.9, and 12.6%) (p<0.05). Fructose, glucose, and citric acid in Melalahti were not influenced by the weather, whereas their concentrations in Mortti and Ola correlated positively with the average temperature in February (Pearson's correlation coefficients = 0.53-0.79, p<0.01) and July (Pearson's correlation coefficients = 0.63-0.87, p<0.01) and negatively with the percentage of the days with a relative humidity of 10-30% from the start of the growth season until the day of harvest (Pearson's correlation coefficients = from -0.47 to -0.76, p<0.01). Positive correlations existed between fructose and glucose (Pearson's correlation coefficients = 0.95-0.96, p<0.01), citric acid and fructose (Pearson's correlation coefficients = 0.57-0.75, p<0.01), as well as between citric acid and glucose (Pearson's correlation coefficients = 0.56-0.70, p<0.01) in the three varieties because of the closely related metabolic pathways.

Regio-distribution of stearic acid is not conserved in chylomicrons after ingestion of randomised, stearic acid-rich fat in a single meal.

Stearic acid from conventional food is well absorbed, but the fate of synthetic randomized stearic acid in fat absorption and subsequent metabolism is unclear. In this study, we examined the postprandial triglyceridemia following an ingestion of randomized stearic acid-rich fat. Following a 12-h fast, nine healthy young males ate a hamburger meal with 16.7 g of stearic acid (30% in triacylglycerol (TAG) sn-2 position, fully randomized). Postprandial blood samples were collected for 450 min, and the stearic acid content in chylomicron (CM, Svedberg flotation rate >400) TAG and the proportion of stearic acid in the sn-2 position were measured by tandem mass spectrometry at peak (180 min) and late (360 min) triglyceridemia. Of all stearic acid in CM TAG, 23% and 22% were in the sn-2 position at peak and late triglyceridemia (P<.004 and P<.001, respectively). This suggests a 68% and 62% conservation of sn-2 stearic acid, respectively. Peak postprandial TAG concentration and incremental area under the TAG curve showed a higher correlation with the fasting CM TAG (r=0.88, P<.01 and r=0.72, P<.05, respectively) than with total fasting plasma TAG (r=0.73, P<.05 and r=0.24, nonsignificant, respectively). In an earlier study, we showed that the absorption efficiency of the stearic acid of the meal was normal, with only marginal amounts of mainly sn-1,3 stearic acid found in the feces. In conclusion, we showed that sn-2 stearic acid is underrepresented in the postprandial CM TAG following an ingestion of fully randomized fat.

The glycaemic response to rolled oat is not influenced by the fat content.

Oat is promoted as a low-glycaemic index food. Our aim was to measure the effect of the fat content of oat in glycaemia and insulinaemia and compare it with the effect of wheat. The study design was a double-blind, randomised cross-over study with four treatment segments. Eight healthy males attended four study sessions in which porridge made from four different raw materials was consumed: rolled oat (O), defatted rolled oat (DO), rolled whole wheat (W) or rolled whole wheat with added oat fat (WF). Available carbohydrate content was analysed enzymatically, and was adjusted to 50 g in each test meal. Fat content per meal was either 6.1 g (O, WF) or approximately 1.9 g (W, DO). Venous plasma glucose, insulin and triacylglycerol concentrations were measured at 0, 30, 60, 90, 120 and 180 min. All products caused a rapid increase in glucose with a peak at 30 min, where W and WF were significantly higher than O (0 = 0.006). Also insulin peaked at 30 min (no differences). A 4.2 g difference in fat content between O and DO or W and WF did not result in any significant differences in their glycaemia or insulinaemia. W and O did not differ in their overall glycaemic or insulinaemic responses. The removal of two-thirds of oat fat did not affect the postprandial plasma triacylglycerol concentration. The present study shows that neither the glycaemic nor the insulinaemic response to rolled oat is affected by the fat content, and that rolled wheat differed from rolled oat in terms of peak glucose concentration only.

Cutin composition of five finnish berries.

The raw cutin (i.e., extractive-free isolated cuticular membrane) fraction from Finnish berries, sea buckthorn (Hippophaë rhamnoides), black currant (Ribes nigrum), cranberry (Vaccinium oxycoccos), lingonberry (Vaccinium vitis-idaea), and bilberry (Vaccinium myrtillus), was depolymerized by NaOMe-catalyzed methanolysis. The composition of cutin monomers was determined by GC-(EI)MS analysis either as methyl esters or as TMSi esters, with OH groups derivatized to TMSi ethers. There was a notable difference in the degree of depolymerization, ranging from 6 to 47%. The extractive-free berry cuticle, that is, raw cutin, thus contains <50% polyester polymer cutin. The predominant cutin monomers were C(16) and C(18) omega-hydroxy acids with midchain functionalities, mainly epoxy and hydroxyl groups. Typically, the major compounds were 9,10-epoxy-18-hydroxyoctadecanoic acid, 10,16-dihydroxyhexadecanoic acid, 9,10,18-trihydroxyoctadecanoic acid, 9,10-epoxy-18-hydroxyoctadec-12-enoic acid, and 18-hydroxyoctadec-9-enoic acid. The amount of epoxyacids was rather high in sea buckthorn ( approximately 70%) and cranberry ( approximately 60%), compared with the other berries. The black currant cutin differed from that of the other berries with a significant portion of hydroxyoxohexadecanoic acid ( approximately 12% of total monomers). This investigation of the cuticular hydroxy acids of five Finnish berries is part of the exploitation of the northern natural resources related to the chemical composition, nutritional value, and sensory properties.