Delayed harvest and cold storage period influence ethylene production, fruit firmness and quality of ‘Cripps Pink’ apple

Prolonged On-Vine vs. Cold of Actinidia eriantha: Differences in Fruit Quality and Aroma Substances during Soft Ripening Stage

In order to find an efficient, economical and feasible method for soft ripening storage of kiwifruit, two softening methods (on-vine, cold) were utilized for the ‘Ganlv-2’ kiwifruit (Actinidia. eriantha) cultivar. A comprehensive evaluation was conducted on the quality changes in ‘Ganlv-2’ under different methods after fruit ripening by principal component analysis and mathematical modeling. Compared to kiwifruit under cold softening, kiwifruit treated with on-vine soft ripening had slightly greater sugar-acid ratios and flesh firmness and higher contents of dry matter, soluble solids, and soluble sugar. The titratable acid content was slightly lower in the on-vine group than in the cold group. The sensory evaluation results manifested little difference in fruit flavor between the two groups. However, at the end of the trial, the overripe taste of the on-vine group was lighter and the taste was sweeter than those of the cold group. More aromatic substances were emitted from the kiwifruit in the on-vine group. According to the mathematic model, there was no significant difference in fruit quality and flavor between the on-vine and traditional cold groups. The fruit in the on-vine group had a stronger flavor and lighter overripe flavor when they reached the edible state. This paper provided a novel storage method of A. eriantha, it can reduce the cost of traditional cold storage and reduce the pressure on centralized harvesting, and the feasibility of this method was verified from the fruit quality.

Modelling of firmness variability of Jonagold apple during postharvest storage

The firmness of Jonagold apples is an important quality attribute during postharvest chain. However, postharvest handlers are faced with variability in the firmness that exists within apples even of those of the same batch and cultivar. Here, Jonagold apples were stored at 1 °C and 4 °C with different controlled atmospheric gas compositions for 170 d, and then exposed to shelf-life conditions for 15 d, and other portion of apples was immediately stored to shelf-life scenario for 21 d. The firmness and ethylene emission of the apples were quantified during storage. A kinetic model equation was established to predict the firmness breakdown of apples depending on storage conditions. The model was based on a stochastic technique that incorporated biological variability in firmness. A relative sensitivity analysis was carried out to analyse the utmost stochastic parameters and fruit-specific data were obtained. The Monte Carlo method was applied to predict how the initial fruit variability in firmness within Jonagold apples propagates throughout the postharvest storage. The simulation outputs suggest that the model established in study may be useful to manage the biological variability and describe how the initial firmness variability propagates during the postharvest chain.

A Near Infrared Spectroscopy (NIRS) and Chemometric Approach to Improve Apple Fruit Quality Management: A Case Study on the Cultivars "Cripps Pink" and "Braeburn"

The potential of near infrared spectroscopy (NIRS) in the wavelength range of 1000–2500 nm for predicting quality parameters such as total soluble solids (TSS), acidity (TA), firmness, and individual sugars (glucose, fructose, sucrose, and xylose) for two cultivars of apples (“Braeburn” and “Cripps Pink”) was studied during the pre- and post-storage periods. Simultaneously, a qualitative investigation on the capability of NIRS to discriminate varieties, harvest dates, storage periods and fruit inhomogeneity was carried out. In order to generate a sample set with high variability within the most relevant apple quality traits, three different harvest time points in combination with five different storage periods were chosen, and the evolution of important quality parameters was followed both with NIRS and wet chemical methods. By applying a principal component analysis (PCA) a differentiation between the two cultivars, freshly harvested vs. long-term stored apples and, notably, between the sun-exposed vs. shaded side of apples could be found. For the determination of quality parameters effective prediction models for titratable acid (TA) and individual sugars such as fructose, glucose and sucrose by using partial least square (PLS) regression have been developed. Our results complement earlier reports, highlighting the versatility of NIRS as a fast, non-invasive method for quantitative and qualitative studies on apples.