Predicting keeping quality of strawberries (cv. `Elsanta') packed under modified atmospheres: an integrated model approach

Postharvest Biology and Technology

Nicholson

Whitmore

2003

Gas exchange rates and quality changes of avocados (Persea americana , Mill., cv. 'Hass') stored at 7 8C in 32 different modified atmosphere (MA) conditions generated using a flow-through system, were monitored to characterise their functional relationship. An integrated modelling approach was used to link rates of quality loss to the rate of gas exchange. This revealed a close quantitative relationship between the gas exchange of 'Hass' avocado fruit on one hand and weight loss, colour change and softening on the other, indicating a direct metabolical link between these processes. High CO 2 lowered the respiratory quotient of avocado, an effect which, based on literature, could be explained by a shift from oxidative phosphorylation into the alternative respiratory pathway. In the model approach, the rates of quality degrading processes were linked to oxidative phosphorylation only, assuming this is where ATP was being produced. At high CO 2 levels at aerobic conditions, unaccounted weight loss data indicated a considerable volatile production which, however, was not qualitatively characterised. Both weight loss and colour change indicated the involvement of anaerobic processes at low O 2 levels. At 2 kPa O 2 and 0 kPa CO 2 no CO 2 injury occurred, while the change in hue was minimal, weight loss was minimised, and softening was almost completely inhibited. At such low O 2 levels, no additional benefit was found from raising the levels of CO 2 .

Section: Colourmentioning

confidence: 99%

“…Also, deterioration of asparagus spears appeared to be strongly related to its own metabolic rate (Brash et al, 1995). suggested using metabolic rate as a rate index for quality changes and Hertog et al (1999) applied this approach to explain the effects of MA on spoilage of strawberries.…”

Section: Introductionmentioning

confidence: 99%

The effect of modified atmospheres on the rate of quality change in ‘Hass’ avocado

Postharvest Biology and Technology

Nicholson

Whitmore

2003

“…By proper control of the levels of oxygen (O 2 ) and carbon dioxide (CO 2 ) in the storage atmosphere, the product's metabolism can be controlled; by reducing the levels of O 2 and increasing the levels of CO 2 , the metabolic rate can be suppressed to the bare minimum, reducing the energy requirements and maximizing the product's shelf life [17,18]. In addition, high CO 2 is known to inhibit microbial growth and thus, from a microbial point of view, contributes to the extension of shelf life [19]. Temperature strongly interacts with the effects of O 2 and CO 2 on both the energy-demanding and -producing processes.…”

Section: (B) Environmental Factors Affecting Product Qualitymentioning

confidence: 99%

Shelf life modelling for first-expired-first-out warehouse management

Phil. Trans. R. Soc. A.

Uysal

Carthy

et al. 2014

105

In the supply chain of perishable food products, large losses are incurred between farm and fork. Given the limited land resources and an ever-growing population, the food supply chain is faced with the challenge of increasing its handling efficiency and minimizing post-harvest food losses. Huge value can be added by optimizing warehouse management systems, taking into account the estimated remaining shelf life of the product, and matching it to the requirements of the subsequent part of the handling chain. This contribution focuses on how model approaches estimating quality changes and remaining shelf life can be combined in optimizing first-expired-first-out cold chain management strategies for perishable products. To this end, shelf-life-related performance indicators are used to introduce remaining shelf life and product quality in the cost function when optimizing the supply chain. A combinatorial exhaustive-search algorithm is shown to be feasible as the complexity of the optimization problem is sufficiently low for the size and properties of a typical commercial cold chain. The estimated shelf life distances for a particular batch can thus be taken as a guide to optimize logistics.

“…In applying models to different fruit, batches or cultivars, it is worthwhile to consider what parameters can be assumed to be either in common for a particular fruit species or cultivar or specific for a particular batch or cultivar (Tijskens and Evelo, 1994;Hertog et al, 1997;Schouten and Van Kooten, 1998;Tijskens et al, 1998;Hertog et al, 1999). Preliminary analysis revealed that the rate constant k could be treated as a constant (k = 0.213 day − 1 ) for all avocados measured.…”

Section: Modelling Colour Change Of Indi6idual A6ocadosmentioning

confidence: 99%

“…A very homogenous population will show a very steep curve, while a heterogeneous population will have a shallow curve. Often, this behaviour can be properly described using the symmetric logistic function Hertog et al, 1999). In other cases, the sigmoidal curve is not symmetric (Bertolini and Tian, 1996) or never reaches 100% (Sarwar and Kunze, 1989;van der Sman et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

The impact of biological variation on postharvest population dynamics

Postharvest Biology and Technology

2002

This paper outlines a mathematical approach to the interpretation of postharvest batch behaviour based on the underlying processes occurring at the level of the individual food items and on the amount of biological variation present. This technique opens the door to a mechanistic interpretation of postharvest batch behaviour, both qualitative and quantitative, enabling the postharvest industries to improve their control of the quality of their produce throughout the postharvest chain. The generic approach is outlined and applied to case studies on shrivelling of 'Braeburn' apples, the colour change of 'Hass' avocados and stress crack development in corn grains.