Karin Haffner

MAP of highbush blueberries: sensory quality in relation to storage temperature, film type and initial high oxygen atmosphere

Abstract Highbush blueberries ( Vaccinium corymbosum L. ‘Bluecrop’) were packed into two film types with different gas permeances and filled with a high-oxygen atmosphere (40% O 2 ) or normal air, and stored at 4 and 12°C. Sensory and chemical attributes were assessed, and the data were submitted to principal component analysis (PCA). The storage temperature was more important than film type and initial atmosphere modification. Important sensory variables for blueberries stored at low temperature were acidic taste and blueberry flavour. At a high storage temperature, bitter taste and storage flavour were the most important sensory variables to describe the samples. The film type was the second most important component, causing differences in the CO 2 content within the packages. Blueberries stored in film with high gas permeance gave the highest scores for sensory texture and blueberry flavour. Initial high oxygen atmosphere had only little influence on sensory quality.

Bilberry extracts induce gene expression through the electrophile response element

Abstract: A number of genes important for detoxification and antioxidant defense induced by mild stress generated by, for example, physical activity/exercise, caloric restriction, or alcohol may provide health benefits by causing the organism to mount such a defense response. More recently, induction of these defenses has also been attributed to phytochemicals or secondary metabolites from dietary plants. Many polyphenols, which constitute a large fraction of these phytochemicals, increase cellular levels of antioxidants, such as glutathione and other components of the detoxification systems, via the transactivation of genes containing electrophile response elements (EpREs) within their promoters. One such gene, γ-glutamylcysteine synthetase, has previously been shown to be positively regulated by quercetin, a flavonoid found in high concentrations in onions, apples, and bilberries through EpRE transactivation. As a further step, we have investigated whether bilberries and quercetin have the ability to induce transcription of Fos-related antigen 1 (Fra-1), which contains two EpREs in its promoter. Fra-1 is a member of the activator protein 1 (AP-1) family of transcription factors and, due to the lack of transactivation domain Fra-1, can suppress activation of AP-1. We present results demonstrating that extracts from bilberries, and the flavonoid quercetin, abundant in bilberries, induce the fra-1 promoter and the cellular content of Fra-1 mRNA. We further provide evidence that this induction is mediated through EpREs.

Compliance, tolerability and safety of two antioxidant-rich diets: a randomised controlled trial in male smokers.

It has been suggested that antioxidants attenuate oxidative stress and prevent oxidative stress-related diseases. Paradoxically, randomised controlled trials (RCT) using pharmacological doses of antioxidant supplements have demonstrated harmful effects in smokers. The aim of the present study was to test the compliance, tolerability and safety of two food-based antioxidant-rich diets in smokers. One of the diets provided antioxidants at levels similar to that used in RCT using supplements which previously have generated harmful effects. The present study followed a randomised, parallel-arm dietary intervention for 8 weeks (n 102) in male smokers (age ≥ 45 years). Participants were randomised to either antioxidant-rich diet, kiwi fruit or control groups. The antioxidant-rich foods provided about 300 mmol antioxidants/week from a wide range of plant-based food items. The kiwi fruit group consumed three kiwi fruits/d. Compliance to both diets was good. Only mild, undesirable events were reported by a minority of the participants. The safety of both diets was demonstrated as no potentially harmful or pro-oxidative effects were observed. In the antioxidant-rich diet group, the mean intake of antioxidants increased from 30 mmol/d at baseline to 62 mmol/d during the intervention. In conclusion, we have demonstrated that male smokers can comply with two food-based antioxidant-rich diets. Furthermore, the present study is the first to demonstrate the tolerability and safety of dietary antioxidants at levels similar to dosages provided in RCT using supplements. Such diets may be useful in future studies investigating whether dietary antioxidants may reduce oxidative stress and related diseases.

Quality of Highbush Blueberry (Vaccinium corymbosum L.) and Bilberry (Vaccinium myrtillus L.) Jam

ABSTRACT Jam from wild bilberries and from the blueberry culti vars ‘Bluecrop’ and ‘Berkeley’ were analyzed by means of sensory profiling and by instrumental measurement of anthocyanins, color, pH and soluble solids. The study shows that bilberry jam has more “bluish black color,” compared to a more “reddish-blue color” and “glossy” surface of the jam from cultivated blueberries. Bilberry jam was less “smooth” and higher in “viscosity” and “berry density” as well as less distinct in “flavor of flowers and fruits,” while the “blueberry flavor and odor” were more distinct in the bilberry jam than that made of highbush blueberries. Analysis of color by means of sensory hue and instrumental a Hunter lab corresponded well, as did saturation measured by the sensory method and chroma instrumentally measured.

Volatile Components of Strawberries (Fragaria×ananassaDuch. cv. ‘Korona’) Under Low Oxygen CA-Storage

Abstract Compounds responsible for off-flavors in fruits kept in anaerobic atmosphere have partly been identified by means of GC-sniff. Strawberries (cv. Korona) were stored for four days at 2.5°C, at 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 4.0 and 5.0% oxygen with nitrogen making up the remainder of the atmosphere. The CO2 level was kept at 0%. Volatile compounds present at higher and lower oxygen levels explained 72% of the total variation, as shown by principal component analysis, mainly due to the greater levels of ethyl esters produced at oxygen levels below 4% than above 4%. The GC-sniff panel identified volatile compounds in agreement with descriptions in the literature. However, it was not possible to distinguish between intensity levels of volatiles of fruits stored at different oxygen levels. Ethyl acetate, ethanol, ethyl butanoate, butyl acetate and ethyl hexanoate showed relatively high concentrations in samples stored at 0.5-2% of oxygen and may together with ethylene cause off-flavors like fermented flavor.