Chemometric Classification of Apple Cultivars Based on Physicochemical Properties: Raw Material Selection for Processing Applications

The potential of red-fleshed apples for cider production

Cider quality is influenced by numerous factors relating to the apples used during production. While extensive research has been done to explore the phenolic content, sensory quality, and storage stability of various apple products, the domain of fermented apple products, such as ciders, remains underrepresented. Red-fleshed apples (RFAs) have naturally high concentrations of phenolic compounds, which indicate their potential in the production of novel cider products. However, a knowledge gap remains regarding the application of RFAs in cider production and how their physicochemical and sensory properties are changed during processing. This review is the first to comprehensively investigate whether and to what extent apple categories (dessert, cider, and RFAs) differ regarding their physicochemical and sensory properties from harvest throughout cider processing. Furthermore, it highlights the importance of a holistic understanding of apple characteristics, encompassing both traditional and RFA varieties in the context of cider production. The findings offer valuable insights for stakeholders aiming to enhance product quality, providing a foundation for future studies on optimizing processing methods for a diverse and appealing range of ciders.

Inactivated mechanisms of high pressure processing combined with mild temperature on pectin methylesterase and its inhibitor

High pressure processing (HPP) of orange juice faces storage issues due to refrigeration need and cloud loss caused by pectin methylesterase (PME). Our previous research indicated that HPP conjunction with pectin methylesterase inhibitor (PMEI) enhanced juice stability, but not fully inactivated PME. This study explored the effectiveness of HPP with mild temperature treatments to fully inactivate PME and sterilize microorganisms in juice, using experimental analysis and molecular dynamics simulation. The findings revealed that PME activity was reduced by 94 % at 600 MPa and 60 °C, with completely inactivating at 80 °C. Conversely, PMEI exhibited resistance to pressure and temperature. Following processes at 600 MPa and above 60 °C, the tail-end helix structure of PME destabilized, with α-helices converting to β-sheets and disrupting hydrogen bonds within molecular chain. Conversely, the structure of PMEI was stable. Additionally, the combination of HPP and temperature treatment enhanced the binding affinity between PME and PMEI.

Optimization and characterization of apple essence microencapsulation utilizing β-cyclodextrin/gum arabic/montmorillonite for fresh-cut apple preservation

Natural apple essence (AE) has been widely used as a flavor enhancer due to its distinct aroma and taste, but its high volatility restricts its broader applications in food products. This study addresses the need for an effective microencapsulation technique to overcome the volatility of AE. The objective was to optimize and characterize the AE microencapsulation using β-cyclodextrin (β-CD), gum arabic (GA), and montmorillonite (MMT) as wall materials. The encapsulation process was optimized by integrating the AHP-CRITIC model with Plackett-Burman and Box-Behnken design methods. SEM, FTIR, and XRD analyses confirmed successful encapsulation and interactions between the AE and the wall materials. The optimized AE microencapsulation was then applied to fresh-cut apples, resulting in significant enhancement in preservation of aroma, taste, and sensory quality. These findings suggest that the developed microencapsulation approach is effective in maintaining storage quality of fresh-cut apples and holds potential for broader applications in the food industry.

Apple russeting-causes, physiology and control measures: A review

MAIN CONCLUSION

This review serves as a critical framework for guiding future research into the causes of russeting and the development of effective control strategies to enhance fruit quality. Russeting is a condition characterized by the formation of brown, corky patches on fruit skin which significantly impairs both the quality and market value of apples. This phenomenon arises from a complex interplay of various biotic and abiotic factors. Among the abiotic factors, environmental conditions, such as light, temperature, and relative humidity, as well as nutrient imbalances and the application of agrochemicals are important, whereas biotic factors include the influence of yeasts, fungi, viruses, and bacteria. The susceptibility of apple cultivars to russeting varies with yellow-fleshed varieties generally exhibiting higher incidences compared to red-fleshed ones. While russeting is partly determined by varietal and genetic factors, it can be mitigated through the implementation of effective cultural practices, nutrient management, plant growth regulators, biological agents, and pesticides. Understanding these dynamics provides valuable insights for developing future research strategies aimed at improving fruit quality and production.

Characterization of key aroma-active compounds in fermented chili pepper (Capsicum frutescens L.) using instrumental and sensory techniques

The aroma profile of fermented chili pepper was analyzed using gas chromatography-mass spectrometry (GC-MS) coupled with chromatography-olfactometry (GC-O). A total of 19 aroma-active compounds were detected, exhibiting aroma intensities spanning from 1.8 to 4.2. And 12 aroma-active compounds were determined as pivotal odorants through odor activity value (OAV) calculation. Concentrations of these aroma-active compounds were quantified and subsequently employed in reconstructing the aroma profile of fermented chili pepper. Quantitative descriptive sensory analysis and electronic nose analysis proved that the aroma profile of fermented chili pepper was basically reconstituted. Omission experiments confirmed that methyl salicylate, linalool, 2-methoxy-3-isobutylpyrazine, and phenylethyl alcohol were the key aroma-active compounds of fermented chili pepper. Moreover, the perceptual interactions between the key aroma-active compounds were investigated. It was found that methyl salicylate masked the floral aroma, while phenylethyl alcohol had an additive effect on the aroma of linalool and 2-methoxy-3-isobutylpyrazine.

Inactivation mechanisms on pectin methylesterase by high pressure processing combined with its recombinant inhibitor

High pressure processing (HPP) juice often experiences cloud loss during storage, caused by the activity of pectin methylesterase (PME). The combination of HPP with natural pectin methylesterase inhibitor (PMEI) could improve juice stability. However, extracting natural PMEI is challenging. Gene recombination technology offers a solution by efficiently expressing recombinant PMEI from Escherichia coli and Pichia pastoris. Experimental and molecular dynamics simulation were conducted to investigate changes in activity, structure, and interaction of PME and recombinant PMEI during HPP. The results showed PME retained high residual activity, while PMEI demonstrated superior pressure resistance. Under HPP, PMEI's structure remained stable, while the N-terminus of PME's α-helix became unstable. Additionally, the helix at the junction with the PME/PMEI complex changed, thereby affecting its binding. Furthermore, PMEI competed with pectin for active sites on PME, elucidating. The potential mechanism of PME inactivation through the synergistic effects of HPP and PMEI.

Enhancing Fresh-Cut Apple Preservation: Impact of Slightly Acidic Electrolyzed Water and Chitosan-Apple Essence Microencapsulation Coating on Browning and Flavor

Fresh-cut apple preservation is a critical concern in the food industry due to the rapid deterioration of texture, color, and flavor. While our previous study introduced apple essence microencapsulation (AEM) to enhance flavor during storage, its impact on overall storage quality was minimal. Thus, this study explores the application of two preservation techniques, namely, slightly acidic electrolyzed water (SAEW) and chitosan-apple essence microencapsulation (CH-AEM) coating, to enhance the quality of fresh-cut apples. Our findings reveal that SAEW treatment significantly reduces the browning index (from 65.38 to 57.36) and respiratory rate (from 5.10% to 4.30% of CO2), and maintains a desirable aroma profile compared to uncoated treatment during 10 days of storage. Additionally, the CH-AEM coating acts as a protective barrier, further preserving the sensory characteristics of fresh-cut apples. Notably, the SAEW-CH-AEM group exhibits superior performance in firmness (8.14 N), respiratory rate (3.37% of CO2), ion leakage (34.86%), and juice yield (47.52%) after 10 days. Our research highlights the synergistic effect of combining these preservation strategies, providing a promising approach for extending the shelf life of fresh-cut apples while maintaining their visual appeal and aromatic quality. These results offer valuable insights for the fresh-cut produce industry, contributing to improved apple product preservation and consumer satisfaction.