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Our investigation delves into the previously uncharted territory of cider composition from Norway. This study aimed to obtain an overview of the qualitative and quantitative compositions of general chemical parameters, polyphenols (individual and total expressed as gallic acids equivalents), selected esters, and selected C6-alcohols in ciders with the PDO label Cider from Hardanger. In total, 45 juice and cider samples from the fermentation process were collected from 10 cider producers in Hardanger in 2019, 2020, and 2021. Individual sugars, acids, ethanol, and 13 individual phenols were quantified using HPLC-UV/RI. Seven ethyl esters of fatty acids, four ethyl esters of branched fatty acids, ten acetate esters, two ethyl esters of hydroxycinnamic acids, and four C6-alcohols were quantified using HS-SPME-GC-MS. For samples of single cultivars (‘Aroma’, ‘Discovery’, ‘Gravenstein’, and ‘Summerred’), the sum of the measured individual polyphenols in the samples ranges, on average, from 79 to 289 mg L−1 (the lowest for ‘Summerred’ and highest for ‘Discovery’ and ‘Gravenstein’). Chlorogenic acid was the most abundant polyphenol in all samples. Ethyl butyrate, ethyl hexanoate, ethyl octanoate, ethyl decanoate, ethyl isobutyrate, ethyl 2-methylbutyrate, isoamyl acetate, and hexanol were present at concentrations above the odour threshold and contributed to the fruity flavour of the Cider from Hardanger.

Saccharomyces cerevisiae is commonly used for the production of alcoholic beverages, including cider. In this study, we examined indigenous S. cerevisiae and S. uvarum strains, both species commonly found in cider from Hardanger (Norway), for their strain-specific abilities to produce volatile and non-volatile compounds. Small-scale fermentation of apple juice with 20 Saccharomyces strains was performed to evaluate their aroma-producing potential as a function of amino acids (AAs) and other physicochemical parameters under the same experimental conditions. After fermentation, sugars, organic acids, AAs, and biogenic amines (BAs) were quantified using the HPLC–UV/RI system. A new analytical method was developed for the simultaneous determination of nineteen AAs and four BAs in a single run using HPLC–UV with prior sample derivatization. Volatile compounds were determined using HS-SPME-GC-MS. Based on 54 parameters and after the removal of outliers, the nineteen strains were classified into four groups. In addition, we used PLS regression to establish a relationship between aroma compounds and predictor variables (AAs, BAs, organic acids, sugars, hydrogen sulfide (H2S) production, CO2 release) of all 19 strains tested. The results of the VIP show that the main predictor variables affecting the aroma compounds produced by the selected yeasts are 16, belonging mainly to AAs.

In organic plant production, nitrogen (N) availability is often a growth-limiting factor. Under such conditions, off-farm waste-derived nutrient resources may be an alternative to meet the N demand. In this study, we described a production method for a shrimp shell (SS) pellet product and evaluated the N fertiliser effect and N recovery efficiency (NRE) in a controlled climate pot experiment with potatoes. The experiment was set up with low, medium and high N levels of SS pellets in comparison with a standard mineral fertiliser (MF) at 9°C, 15°C and 21°C. In a separate study, we examined the loss of N as N2O from SS pellets in comparison with SS powder in a 100 days incubation experiment. The results documented the possibility to formulate a fertiliser pellet product from SS, and that SS pellets were an effective N fertiliser in potato at all growth temperatures. Nevertheless, a slightly slower development and lower tuber yields than for MF indicated a delayed N-availability from SS pellet fertiliser. NRE after use of MF was around 90%, and about 70% for the different levels of SS pellets. The incubation experiment showed a higher rate of available N for SS powder than for pellets (67% and 39%, respectively) after 100 days of incubation at constant humidity and temperature. This difference was attributed to a lower degree of dissolved materials and a higher rate of denitrification and N2O emissions for pellets than for powder, probably caused by differences in physical properties, occurrence of anoxic hotspots and higher microbial activity around and inside the SS pellets.