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BACKGROUND High cell density in cultures of microalgae is a key factor to recover biomass and extract metabolites of interest. A fed batch tubular reactor (FBTR) and semi‐continuous reactor (SCR) with f/2 Guillard Medium (f/2GM) and algal medium (AM) were evaluated. Both modes were operated under completely defined conditions to assess their effect on cell density, and lipid, protein and carbohydrate productivity of the microalgae Nannochloropsis oculata. RESULTS Results show that the FBTR promotes the highest cell density for both culture media, achieving 525 ± 1.84×106 cell mL‐1. With AM in the SCR, specific growth rate, productivities of biomass and lipids were the highest, as well as content of protein (48%), lipid (52.1%) and carbohydrates (17%). No significant differences were found in saturated fatty acids composition, whereas unsaturated fatty acids composition was affected by the operating regimen, this being higher in the FBTR. CONCLUSION The use of AM in both operating modes, FBTR and SCR, increased the cell density and improved the lipid content of N. oculata. A good option would be to combine both culture modes; first, use the FBTR to obtain high cell densities and then apply the SCR mode to increase lipid productivity; finally, an important quantity of high‐value products could be recovered. © 2017 Society of Chemical Industry

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There is a lack of region-adapted tools to evaluate diet as a risk factor for cardiovascular disease (CVD) in adolescents. The study aim was to evaluate the reproducibility and validity of a paper-based and region-adapted food frequency questionnaire (FFQ) designed to assess CVD-related food and nutrient intakes of adolescents from Northwest México. The study design was cross-sectional. The FFQ was developed in a two-step process: prototype designing and a pilot test, with re-tested in a 3-month period, along with two administrations of 24 h-recall (24 hR). Pearson's and intra-class correlation coefficients (PCC and ICC) were assessed. Bland–Altman plots, limits of agreement and quintile classifications were carried out. Participants (n 221) were 53·8 % male, 18·5 ± 0·4 years old. Reproducibility had a median PCC = 0·66 for processed meats, ranging from 0·40 (saturated fat) to 0·74 (fish & shellfish), P = 0·001. ICC ranged from 0·53 (saturated fat) to 0·80 (sodium; and nuts, seeds and legumes), P = 0·001. Validity comparing FFQ1 v. 24 hR mean, PCCs ranged from 0·12 (P = 0·06) to 0·95 (P = 0·001), and ICC from 0·20 (P = 0·048) to 0·88 (P = 0·001); comparing FFQ2 v. 24 hR mean, PCCs ranged from 0·07 (P = 0·25) to 0·46 (P = 0·001), and ICC from 0·15 (P = 0·106) to 0·58 (P = 0·001). The FFQ overestimated the intake of all food groups and nutrients (P < 0·05), while Cohen's κ showed coefficients lower than 0·20. The proposed FFQ represents a moderately validated tool to estimate CVD-related food and nutrient intakes as a risk factor, which can be used in combination with multiple administrations of 24 hRs, as a critical mean in future interventions intended to reduce cardiometabolic risk in adolescents.