Chemical Characterization, Sensory Definition and Prediction Model of the Cider Dryness from New York State Apples

Cider is a fermented drink obtained from apple juice. As a function of the used apple cultivar, cider can be classified in four different categories (dry, semi-dry, semi-sweet, sweet), distinguished by the attribute of "dryness," which reflects the sweetness and softness perceived. The dryness level is defined by scales (IRF, NYCA scales) based on the residual sugar, titratable acidity and tannin contents. Despite some adjustments, these scales show limitations in the prediction of actual perceived dryness, as they cannot consider the complicated interrelation between combined chemical compounds and sensory perception. After defining the perceived sensory dryness and its sensory description by using the quantitative descriptive analysis (QDA) method, a multivariate approach (PLS) was applied to define a predictive model for the dryness and to identify the chemical compounds with which it was correlated. Three models were developed, based on three different sets of chemical parameters, to provide a method that is easily applicable in the ordinary production process of cider. The comparison between the predicted rating and the relative scales scores showed that the models were able to predict the dryness rating in a more effective way. The multivariate approach was found to be the most suitable to study the relation between chemical and sensory data.

Enantioselective fate of famoxadone during processing of apple cider and grape wine

Famoxadone enantiomers were separated on Lux Amylose-1 chiral column and determined by ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS). The half-lives of R-(-)-famoxadone and S-(+)-famoxadone were 69.3 and 86.6 h in apple cider, 231.0 and 346.5 h in apple pomace, 69.3 and 77.0 h in grape wine, and 231.0 and 346.5 h in grape pomace, respectively. The enantiomeric fraction (EF) values decreased gradually from 0.498, 0.499, and 0.500 (0 h) to 0.404, 0.374, and 0.427 (144 h) and then increased gradually to 0.474, 0.427, and 0.422 (312 h) in apple cider, grape wine, and grape pomace. The EF value in apple pomace decreased gradually from 0.499 (0 h) to 0.450 (168 h) and then increased gradually to 0.482 (312 h). The processing factors (PFs) for famoxadone ranged from 0.014 to 0.024 in the overall process. The residue of famoxadone reduced 94.7-97.4% after the fermentation process.

Impact of polyphenols on the headspace concentration of aroma compounds in apple cider

BACKGROUND

To study the effect of polyphenols on the release of aroma compounds in apple cider, the impact of (-)-epicatechin, hydrocaffeic acid and phloridzin on volatility of 12 typical aroma compounds was investigated by headspace solid phase microextraction and gas chromatography-mass spectrometry.

RESULTS

Analysis of variance results showed that increased concentrations of the phenolic compounds significantly affected the headspace concentration of most aroma compounds. The three polyphenols induced a volatility decrease for the majority of hydrophobic aroma compounds, while they exhibited an opposite behavior by salting out some hydrophilic alcohols. (-)-Epicatechin and hydrocaffeic acid showed a higher retention effect on most hydrophobic aroma compounds than phloridzin did.

CONCLUSION

This study showed that the polyphenols had varying effects on aroma compound volatility in apple cider. The physicochemical characteristics and spatial conformation of polyphenols and aroma compounds influenced the magnitude of aroma-polyphenol interaction in apple cider. Understanding the effects of polyphenols on aroma release can improve the prediction of aroma profiles through chemical analysis, which assists cidermakers in improving the aroma quality of apple cider. © 2018 Society of Chemical Industry.

Fermentation of Apple Juice with a Selected Yeast Strain Isolated from the Fermented Foods of Himalayan Regions and Its Organoleptic Properties

Twenty-three Saccharomyces cerevisiae strains isolated from different fermented foods of Western Himalayas have been studied for strain level and functional diversity in our department. Among these 23 strains, 10 S. cerevisiae strains on the basis of variation in their brewing traits were selected to study their organoleptic effect at gene level by targeting ATF1 gene, which is responsible for ester synthesis during fermentation. Significant variation was observed in ATF1 gene sequences, suggesting differences in aroma and flavor of their brewing products. Apple is a predominant fruit in Himachal Pradesh and apple cider is one of the most popular drinks all around the world hence, it was chosen for sensory evaluation of six selected yeast strains. Organoleptic studies and sensory analysis suggested Sc21 and Sc01 as best indigenous strains for soft and hard cider, respectively, indicating their potential in enriching the local products with enhanced quality.

Kinetics of patulin degradation in model solution, apple cider and apple juice by ultraviolet radiation

Patulin is a mycotoxin produced by a wide range of molds involved in fruit spoilage, most commonly by Penicillium expansum and is a health concern for both consumers and manufacturers. The current study evaluated feasibility of monochromatic ultraviolet (UV) radiation at 253.7 nm as a possible commercial application for the reduction of patulin in fresh apple cider and juice. The R-52G MINERALIGHT® UV bench top lamp was used for patulin destruction. It was shown that 56.5%, 87.5%, 94.8% and 98.6% reduction of patulin can be achieved, respectively, in the model solution, apple cider, apple juice without ascorbic acid addition and apple juice with ascorbic acid addition in 2-mm thickness sample initially spiked by 1 mg·L(-1) of patulin after UV exposure for 40 min at UV irradiance of 3.00 mW·cm(-2). A mathematic model to compare the degradation rate and effective UV dose was developed. The effective UV doses that were directly absorbed by patulin for photochemical reaction were 430, 674, 724 and 763 mJ·cm(-3), respectively. The fluence-based decimal reduction time was estimated to 309.3, 31.3, 28.9 and 5.1 mW·cm(-2)·min, respectively, in four media mentioned above. The degradation of patulin followed the first-order reaction model. The time-based and fluence-based reaction rate constants were determined to predict patulin degradation. The time-based reaction rate constant of samples treated in dynamic regime with constant stirring (model solution: 2.95E-4 s(-1), juice: 4.31E-4 s(-1)) were significantly higher than samples treated in static regime (model solution: 2.79E-4 s(-1), juice: 3.49E-4 s(-1), p < 0.05) when applied UV irradiance and sample thickness were consistent. The reaction rate constant of patulin degradation in apple juice was significantly higher than model solution (p < 0.05). Although further investigations are still needed, the results of this study demonstrated that UV radiation may be an effective method for treating patulin-containing apple cider and juice.

Increased Detection of Acid-Injured Escherichia coli O157:H7 in Autoclaved Apple Cider by Using Nonselective Repair on Trypticase Soy Agar †

Three different acid-resistant strains of Escherichia coli O157:H7 were inoculated individually and as a cocktail into sterile apple cider (pH 3.2) at a level of approximately 10⁵ cells per ml and incubated at 2°C. Samples were plated on Trypticase soy agar (TSA), violet red bile agar (VRBA), sorbitol MacConkey agar (SMA), and Petrifilm E. coli count plates (Petrifilm) at 24-h intervals. Repair of acid-injured cells was assessed by surface plating cider samples on TSA and allowing a 2-h room-temperature incubation period followed by overlaying with double-strength VRBA or SMA. Since SMA is a surface plate medium, the repair procedure was modified by overlaying SMA with Trypticase soy broth after 2 h of room-temperature incubation. Populations of all three strains and the cocktail of strains decreased rapidly in apple cider and approached undetectable levels within 72 h. At 24 and 48 h, 98.4% and >99% of the E. coli populations were injured, respectively. Repair procedures significantly (α = 0.05) increased detection of E. coli O157:H7. After 72 h E. coli O157:H7 was not detected by using SMA and Petrifilm; however, it was detected using repair procedures. Although detection levels were increased with resuscitation procedures, the levels detected were still lower than those obtained using nonselective TSA. This research confirms the need for special recovery steps when analyzing acidic food products suspected of containing E. coli O157:H7.

Survival of Escherichia coli O157:H7 during Fermentation of Apple Cider

Survival of Escherichia coli O157:H7 in fermenting and nonfermenting fresh apple cider was determined. Populations of E. coli O157:H7 were reduced from 6.4 log CFU/ml to undetectable levels (detection limit of 0.5 log CFU/ml) in fermenting cider after 3 days at 20°C and from 6.5 log CFU/ml to 2.9 log CFU/m1 after 10 days at 20°C in nonfermenting cider. After 1 day of incubation, recovery of E. coli O157:H7 from fermenting and nonfermenting cider was statistically (P < 0.01) lower on sorbitol MacConkey agar than on tryptone soya agar supplemented with cycloheximide. These results suggest that substantial portions of the surviving E. coli O157:H7 populations were sublethally injured by cider components (i.e., acid and ethanol). The pH of fermenting cider was not significantly different (P > 0.05) from that of nonfermenting cider throughout the 10-day test period. Final ethanol concentrations in fermenting cider reached 6.01% (vol/vol) after 10 days at 20°C. Inactivation of E. coli O157:H7 in fermenting cider is attributed to the combined effects of pH and ethanol. Results of this study indicate that E. coli O157:H7 is capable of survival in fresh apple cider at 20°C, while alcoholic fermentation of fresh cider is an effective means of destroying this pathogen.

Escherichia coli O157: H7 Acid Tolerance and Survival in Apple Cider

The survival of two Escherichia coli O157:H7 (ATCC 43889 and 43895) and a control strain E. coli was compared in apple cider and in Trypticase soy broth (TSB) adjusted to low and high pH. The O157:H7 strains were detectable in apple cider after 14 to 21 days at 4°C, whereas the control strain could not be detected (> 4-log reduction) after 5 to 7 days. During the first 14 days of storage at 4°C, the levels of strain 43889 decreased by ~3 logs, whereas levels of strain 43895 were unchanged. Survival of O157:H7 strains and the control strain were unaffected by the presence of potassium sorbate or sodium benzoate, except in one instance. Sodium benzoate caused a decrease of 57% in strain 43895 after 21 days, but ~10⁴ CFU/ml still remained. In TSB adjusted to pH 2, 3, 4, 11 or 12, strain 43895 was again the more resistant of the O157:H7 strains, both of which were more durable than the control strain. The O157:H7 strains (especially strain 43895) withstood pH 2 with a minimal drop in CPU after 24 h, whereas no viable organisms were detectable after this time at pH 12. At these extremes of pH, survival was generally greater at 4°C than at 25°C. Despite differences between strains, these results show that E. coli O157:H7 is exceptionally tolerant of acid pH.