French Cider Research Articles

Factors leading to the expression of “framboisé” in French ciders

During the last decade, observations on cider production sites allowed for some hypotheses to be made concerning relationships between “framboisé” (cider-sickness) development and physical and chemical cider parameters as well as some process operations. Although Zymomonas mobilis has long been known to cause cider-sickness in British ciders, it had never been detected in France until recently from a number of “framboisé” cases. The possibility to trigger “framboisé” in cider by inoculation of the bacterium allowed for a better understanding of the factors leading to “framboisé” development in ciders. The stage of the malo-lactic fermentation, amount of dissolved of oxygen, pH, combined effect of pH and sulfur dioxide and residual amount of utilizable yeast nitrogen (YAN) were studied. The main factor affecting cider sensitivity to “framboisé” is the amount of YAN. If the amount of YAN is sufficient, the development of “framboisé” will mainly be influenced by pH (sulfur dioxide playing a minor role).

French cider characterization by sensory, technological and chemical evaluations

A set of 90 ciders among them 50 “brut” (near dry), 30 “demi-sec” (half dry) and 10 “doux” (sweet) were collected and analysed to get a data base of about 180 variables including processing conditions, sensory descriptors and physicochemical variables. This data set was treated by a multiple factor analysis (MFA) using the sensory and analytical data as active variables whereas the “processing conditions” data were introduced as illustrative variables. Two MFAs was carried out separating the less sweet (“bruts”) from the sweeter (“demi secs” and “doux”) ciders. For both sets, the MFAs showed a strong polarization of the ciders characteristics: fruity/flowery flavours are associated with cooked flavours and opposed to the descriptors “ animal” (animal), “ sous-bois” (underwood), “ fond de cuve” (vat dregs) themselves associated with bitterness and astringency and also “pomme/cidre” (cider/apple) flavours. The industrial ciders located on axis 1 near the fruity and cooked odours whereas the ciders of small scale producers were close to the second group of flavours and tastes.

“Framboisé” spoilage in French ciders: Zymomonas mobilis implication and characterization

Biodiversity of 17 Zymomonas mobilis strains isolated from French “framboisé” ciders from 7 different geographical areas of France was analysed using random amplified polymorphic DNA (RAPD) and 6 different strain fingerprints were observed. One of the fingerprints was identical for 10 of the 17 cases. No correlation between geographical origin and strain fingerprint was observed. In parallel, the cider-making process was followed from the orchard to the final product for Z. mobilis presence. Detection of the bacterium only occurred during the fermentation process. The French isolate, strain AN0101, recently proposed as a novel subspecies ( Z. mobilis subsp. francensis) was characterized in a synthetic medium using various growth conditions that can be encountered during cider-making ( T (°C), pH, ethanol, SO 2, polyphenols) to determine growth limits. Results clearly showed that cider is in a risk zone for Z. mobilis contamination as this bacterium was able to grow at temperatures as low as 4 °C, in pH range from 3.5 to 6.0, in 0–8 ml/100 ml ethanol, at the legal limit of 200 mg/l SO 2 and in the presence of a cider marc polyphenol extract up to 3 g/l. These results should allow for a better understanding of Z. mobilis conditions of contamination in cider and lead to possible preventive measures in the future.

Polyphasic study of Zymomonas mobilis strains revealing the existence of a novel subspecies Z. mobilis subsp. francensis subsp. nov., isolated from French cider

Zymomonas mobilis strains recently isolated from French 'framboisé' ciders were compared with collection strains of the two defined subspecies, Z. mobilis subsp. mobilis and Z. mobilis subsp. pomaceae, using a polyphasic approach. Six strains isolated from six different regions of France were compared with three strains of Z. mobilis subsp. mobilis, including the type strain LMG 404T, and four strains of Z. mobilis subsp. pomaceae, including the type strain LMG 448T, using phenotypic and genotypic methods. For phenotypic characterization, both physiological tests and SDS-PAGE protein profiles revealed significant differences between the two known subspecies and the French isolates; three distinct groups were observed. These findings were further confirmed by random amplified polymorphic DNA and repetitive extragenic palindromic-PCR genotyping methods in which the French isolates were clearly distinguished from the other two subspecies. Sequence analysis of a fragment ranging from 604 to 617 nucleotides corresponding to the 16S-23S rRNA gene intergenic spacer region (ISR), a 592 nucleotide HSP60 gene fragment and a 1044 nucleotide gyrB gene fragment confirmed the presence of three distinct groups. The French strains exhibited almost 94 % similarity to the ISR, 90 % to HSP60 and 86 % to gyrB sequences of the three collection strains of Z. mobilis subsp. mobilis and 87, 84 and 80 % sequence similarity, respectively, was observed with the four Z. mobilis subsp. pomaceae strains. Based on both the phenotypic and genotypic results, the French strains are proposed to represent a novel subspecies, Zymomonas mobilis subsp. francensis subsp. nov. Strain AN0101T (= LMG 22974T = CIP 108684T) was designated as the type strain.

Yeast ecology in French cider and black olive natural fermentations

In this study, rDNA ITS restriction analysis was used to identify yeasts from two naturally fermented products: French ciders and black olives. In cider musts and bottled ciders, the PCR-RFLP method generated 15 different ITS/RFLP profiles for a total of 208 isolates. The predominant yeasts corresponded to Saccharomyces bayanus, Saccharomyces cerevisiae, Lachancea cidri and Dekkera anomala. Three identified species: Candida sake, Candida tropicalis and Kluyveromyces marxianus had never been described before in ciders. For the black olive fermentation, the method allowed for identification of 11 profiles for a total of 137 isolates. A sequential apparition of yeasts was observed with Pichia anomala, Candida boidinii and Debaryomyces etchellsii being the predominant species. Four isolates did not correspond to any known species based on the sequencing of the D1/D2 region of the 26S rRNA gene. By using the rDNA ITS method, valuable information on yeast population biodiversity and dynamics in the naturally fermented food products studied was obtained.

Chemometric classification of Basque and French ciders based on their total polyphenol contents and CIELab parameters

Total polyphenol contents, estimated by Folin–Ciocalteu method, and CIELab chromatic parameters were determined in Basque and French ciders with the aim of developing a classification system to confirm the authenticity of ciders. A preliminary study of data structure was performed by a multivariate data analysis using chemometric techniques such as cluster analysis and principal component analysis. Supervised pattern recognition methods, such as linear discriminant analysis, K-nearest neighbours (KNN), soft independent modelling of class analogy and multilayer feed-forward artificial neural networks (MLF-ANN), provided classification rules for the two categories based on the experimental data. KNN results for Basque ciders afforded an excellent performance in terms of recognition and prediction abilities (99%), providing a useful tool to detect genuine Basque ciders. Despite KNN and MLF-ANN giving the best results for French ciders, with a success rate of prediction ability around 91%, this would not be acceptable for authentication purposes.

Chemometric characterisation of Basque and French ciders according to their polyphenolic profiles.

Polyphenolic compositions of Basque and French ciders were determined by HPLC-DAD following thiolysis, in order to characterise and differentiate these beverages and then develop a classification system capable of confirming the authenticities of both kinds of cider. A data set consisting of 165 cider samples and 27 measured features was evaluated using multivariate chemometric techniques, such as cluster analysis and principal component analysis, in order to perform a preliminary study of data structure. Supervised pattern recognition techniques such as linear discriminant analysis (LDA), K-nearest neighbours (KNN), soft independent modelling of class analogy (SIMCA), and multilayer feed-forward artificial neural networks (MLF-ANN) attained classification rules for the two categories using the chemical data, which produced satisfactory results. Authentication systems obtained by combining two of these techniques were proposed. We found that SIMCA and LDA or KNN models achieved 100% hit-rates, since LDA and KNN permit the detection of every Basque cider and SIMCA provides a model for Basque cider that excludes all French ciders. Polyphenolic profiles of the ciders provided enough information to be able to develop classification rules for identifying ciders according to their geographical origin (Basque or French regions). Chemical and organoleptic differences between these two types of cider are probably due to the original and distinctive cidermaking technologies used for their elaboration. Using polyphenic profiles, about 80% of French ciders could be distinguished according to their region of origin (Brittany or Normandy). Although their polyphenolic profiles did not provide enough information to achieve an authentication system for Breton and Norman ciders.

Variability of the polyphenolic composition of cider apple (Malus domestica) fruits and juices.

Five French cider apple varieties were compared on the basis of their detailed polyphenol profile in the cortex and in the juices. Among the factors studied, variety was the most important variability factor in fruits, whereas polyphenol profiles showed an overall stability from one year to another, and a limited decrease of polyphenol concentration was observed during the starch regression period of fruit maturation. In juices, procyanidins remained the preponderant polyphenol class with concentrations up to 2.4 g/L even in centrifuged juices. Compared to the fruits, the average degree of polymerization of procyanidins was significantly reduced in the juice. Centrifugation of the crude juice had only minor effects on the polyphenol composition. For one variety, highly polymerized procyanidins with average degrees of polymerization of 25 were shown to be soluble in the centrifuged juice at a concentration of close to 1.2 g/L. Oxygenation of the juices during processing resulted in a significant decrease of all classes of native polyphenols. Catechins and procyanidins were particularly affected by oxidation, whereas caffeoylquinic acid was partly preserved. The transfer of polyphenols after pressing was maximal for dihydrochalcones and minimal for procyanidins with extraction yield values close to 80 and 30%, respectively.

Microbiological Origin of “Framboisé” in French Ciders

J. Inst. Brew. 109(4), 299–304, 2003 In this work, populations of acetic acid bacteria and zymomonads were studied and the kinetics of several parameters followed in three ciders: one “healthy”, one “framboise” and one stabilized. In the “framboise” cider, correlations were observed between cider-sickness symptoms (reduction of sugars, production of CO2 and increase of ethanol and acetaldehyde content) and the presence of a bacteria growing on a zymomonads medium. When inoculated in a “healthy” cider at pH 4.1, the bacteria induced cider-sickness symptoms while no symptoms were observed at pH 3.7. The bacteria were characterized and identified by sequencing of the 16S rDNA region and corresponded to a strain of Z. mobilis pomaceae. A detection study on 17 spoiled ciders and 5 “healthy” ciders appeared to indicate that there was a high prevalence of this microorganism involved in “framboise” cases in France. To our knowledge this is the first description of the involvement of Z. mobilis strains in French “framboise” ciders.

Reversed-Phase HPLC following Thiolysis for Quantitative Estimation and Characterization of the Four Main Classes of Phenolic Compounds in Different Tissue Zones of a French Cider Apple Variety (Malus domestica Var. Kermerrien)

Phenolic compounds, which are present in the epidermis zone, parenchyma zone, core zone, and seeds of fruit (Malus domestica var. Kermerrien), were extracted from freeze-dried material by three successive solvent extractions. The dry methanol extract and the dry aqueous acetone extracts were analyzed using reversed-phase HPLC coupled with diode array detection following thiolysis to quantify phenolic compounds according to their classes (hydroxycinnamic acid derivatives, flavan-3-ols, flavonols, and dihydrochalcones). The method is suitable for the determination of the relative proportions of the different classes of polyphenols and provided information on the constitutive units and the average degree of polymerization of oligomeric and polymeric procyanidin structures. Results showed that procyanidins are the predominant phenolic constituents in cider apple fruits, much of them corresponding to highly polymerized structures. Keywords: Apple; phenolics; procyanidins; cider; HPLC; thiolysis

Absolute Configuration and Conformation of 1,3-Dioxanes from Cider

In extracts obtained by liquid-liquid extraction from French cider (2S,4R)- and (2R,4R)-2-methyl-4-pentyl-1,3-dioxane, 1a and 1b as well as (2S,4R)- and (2R,4R)-2-methyl-4-(2'(Z)-pentenyl)-1,3-dioxane, 2a and 2b, were identified by capillary gas chromatography (HRGC) and capillary gas chromatography-mass spectrometry (HRGC-MS). Absolute configuration and conformation of the 1,3-dioxanes was determined by nuclear magnetic resonance (NMR) spectrometry techniques [ 13 C, 1 H, nuclear Overhauser enhancement (NOE), and H/H homonuclear decoupling], multidimensional gas chromatography (MDGC), and by comparison with synthesized reference compounds. A nonenzymatic formation of 1a and 1b and 2a and 2b during fermentation of apple juice was proposed leading to 22, 8, 2, and <1 mg/L of 1a, 2a, 1b, and 2b, respectively in cider.

Liquid Chromatographic Determination of Patulin in French Apple Ciders

Abstract A liquid chromatographic (LC) method was developed for detection and quantitation of patulin in French apple ciders. Cider was applied to an Extrelut column; patulin was extracted with ethyl acetate- toluene, and the extract was cleaned up on a Sep-Pak Florisil cartridge. Patulin was detected with a UV photometer at 275 nm. A reversed-phase column and an elution gradient were used for LC separation. Patulin recoveries at 3 levels ranged from 90.4 to 91.7%. Repeatability at 50 and 100 ppb levels did not exceed 15%. The calibration graph was rectilinear from 0.2 to 1 μg/mL patulin working solutions corresponding to 20-100 ppb patulin in sample. The quantitation limit was 10 ppb. The method represents an improvement in selectivity for determination of patulin in a specific matrix such as French apple cider.

High-performance liquid chromatography of the phenolic compounds in the juice of some French cider apple varieties

The phenolic compounds chlorogenic acid, p-coumaric acid, protocatechuic acid, (+)-catechin, (−)-epicatechin, phloridzin and di-, tri- and tetrameric procyanidins in apple juice were separated by reversed-phase high-performance liquid chromatography on a C 18 column using a methanol-dilute hydrochloric acid solvent gradient. Absorbance ratios and UV spectrometry were used to identify the separated phenolic compounds and to check their purity.