R.E. Schouten

Keeping quality of cucumber fruits predicted by biological age

Abstract In the absence of defects, colour is one of the few practical criteria for assessing cucumber ( Cucumis sativus L.) quality. However, cucumbers with the same colour at harvest can exhibit large differences in quality upon reaching the consumer. Photochemical yield (Φ PSII ), photochemical quenching ( q P ) and a photosystem I evaluation ( k e ), as internal quality measurements, were used in combination with an external quality measurement, represented by the colour, to test if the keeping quality could be predicted on the basis of these measurements. Keeping quality is defined as the time for a cucumber to reach a certain predefined colour limit. To test the hypothesis, colour changes for 2000 cucumbers were measured during storage at 20°C and 100% RH. The colour data were fitted to a model where a correction for biological age ( C ba ) was applied to each individual cucumber. The correction for biological age could be linked to the measured Φ PSII , q P and k e values. Statistical analyses resulted in values for the maximum (green) and minimum colour (yellow) for each cucumber. The minimum colour could be correlated with different cultivars and the maximum colour with plant growing conditions. After a suitable transformation by a neural network, C ba could be estimated based on the values of Φ PSII , q P and k e and the initial colour. Predictions on the keeping quality by the model resulted in an explained variance of 74% ( R 2 adj =0.74).

Predictability of keeping quality of strawberry batches

Postharvest life of strawberries is largely limited by Botrytis cinerea infection. It is assumed that there are two factors influencing the batch keeping quality: the Botrytis pressure and the resistance of the strawberry to infection. The latter factor will be discussed in this article. A colour model is presented that describes the development of red colour and anti-fungal function of individual strawberries over time. The model was fitted to colour data from strawberries grown at two different nutrient densities (EC) and stored per batch at 5, 10 or 16 °C and constant vapour pressure deficit after harvest. A batch was defined as all strawberries from one EC and one harvest. Spoilage per batch was recorded daily during storage. The fitted initial spoilage per batch was found to relate to the fitted average amount of precursor of both the colour and the anti-fungal compounds. Batch keeping quality could be derived from the initial batch colour distributions for the low nutrient batches. Also, batch keeping quality correlated highly with the time between harvest dates for the low EC batches. An explanation for the ability to link colour distributions to keeping quality without having to use a term describing the pH is presented from pigment HPLC measurements of sub-batches. Indications that the colour distributions of high EC batches may be subject to substantial co-pigmentation are presented. For a practical implementation of predicting keeping quality of batches additional research is needed, especially regarding different Botrytis pressures between greenhouses.

Factors Affecting Quality and Health Promoting Compounds during Growth and Postharvest Life of Sweet Cherry (Prunus avium L.)

Sweet cherries are attractive fruits due to their taste, color, nutritional value, and beneficial health effects. Sweet cherry is a highly perishable fruit and all quality attributes and the level of health promoting compounds are affected by growth conditions, picking, packing, transport, and storage. During production, the correct combination of scion × rootstock will produce fruits with higher firmness, weight, sugars, vitamins, and phenolic compounds that boost the fruit antioxidant activity. Orchard management, such as applying drip irrigation and summer pruning, will increase fruit sugar levels and total phenolic content, while application of growth regulators can result in improved storability, increased red coloring, increased fruit size, and reduced cracking. Salicylic acid, oxalic acid, acetylsalicylic acid, and methyl salicylate are promising growth regulators as they also increase total phenolics, anthocyanins, and induce higher activity of antioxidant enzymes. These growth regulators are now also applied as fruit coatings that improve shelf-life with higher antioxidant enzyme activities and total phenolics. Optimizing storage and transport conditions, such as hydro cooling with added CaCl2, chain temperature and relative humidity control, are crucial for slowing down decay of quality attributes and increasing the antioxidant capacity. Application of controlled atmosphere during storage is successful in delaying quality attributes, but lowers ascorbic acid levels. The combination of low temperature storage in combination with modified atmosphere packaging (MAP) is successful in reducing the incidence of fruit decay, while preserving taste attributes and stem color with a higher antioxidant capacity. A new trend in MAP is the use of biodegradable films such as micro-perforated polylactic acid film that combine significant retention of quality attributes, high consumer acceptability, and a reduced environmental footprint. Another trend is to replace MAP with fruit edible coatings. Edible coatings, such as various lipid composite coatings, have advantages in retaining quality attributes and increasing the antioxidant activity (chitosan) and are regarded as approved food additives, although studies regarding consumer acceptance are needed. The recent publication of the sweet cherry genome will likely increase the identification of more candidate genes involved in growing and maintaining health related compounds and quality attributes.

Basic principles of analysing biological and technical variation in non-destructive data

A guide to include variation in statistical analysis of non-destructive data.Biological and technical variation are split up and estimated separately.Huge increase in reliability of the estimated parameters.Principles explained with simulated data on exponential decay.Applicability demonstrated on several examples from practise. More and more, the omnipresent variation between individual items in a batch is taken into account by using special analysing techniques like mixed effects and indexed regression. In this paper the assumptions upon which these techniques are based, are explained, based on a simulated data set. The most important issue is the separation of biological variation and the technical variation (or measuring error). The techniques are further elucidated with some examples from practise (skin colour apples in storage, softening of melons in storage and water loss in plums, melons and mandarins), to show the increased reliability of the analyses. Since variation is always present in any measured data set, the techniques are applicable in all fields working with living material.

Designing New Supply Chain Networks: Tomato and Mango Case Studies

Consumers expect product availability as well as product quality and safety in retail outlets. When designing or re-designing fruit and vegetables supply chain networks one has to take these demands into consideration next to traditional efficiency and responsiveness requirements. In food science literature, much attention has been paid to the development of Time-Temperature Indicators to monitor individually the temperature conditions of food products throughout distribution as well as quality decay models that are able to predict product quality based upon this information. This chapter discusses opportunities to improve the design and management of fruit and vegetables supply chain networks. If product quality in each step of the supply chain can be predicted in advance, good flows can be controlled in a pro-active manner and better chain designs can be established resulting in higher product availability, higher product quality, and less product losses in retail. This chapter works towards a preliminary diagnostic instrument, which can be used to assess supply chain networks on QCL (Quality Controlled Logistics). Findings of two exploratory case studies, one on the tomato chain and one on the mango chain, are presented to illustrate the value of this concept. Results show the opportunities and bottlenecks for quality controlled logistics depend on product—(e.g. variability in quality), process—(e.g. ability to use containers and sort on quality), network- (e.g. current level of cooperation), and market characteristics (e.g. higher prices for better products).

Similarities between quality and health promoting compounds as a result to stress.

Similarities Between Quality and Health Promoting Compounds as a Result to Stress Antioxidants are produce by plants as a defence mechanism against stress. It is not unlikely that quality related properties are related to that stress induced production system (secondary metabolites). Based on purely theoretical considerations and on scarce information from literature and experts, a highly speculative model was developed to investigate the possible importance of stress levels on the production of health promoting compounds and quality related properties. Simulations with that model, using completely arbitrary parameter values showed that a relation exist between applied stress and production of these beneficiary compounds. Zależności Pomiędzy Jakością a Prozdrowotnymi Składnikami Jako Wynik Stresu Antyutleniacze są produkowane przez rośliny na skutek uruchamiania mechanizmu obronnego przeciwko stresowi. Jest niewykluczone, że cechy odpowiedzialne za jakość są związane z tym mechanizmem, indukowanym przez stres. Opierając się na czysto teoretycznych rozważaniach i na nielicznych doniesieniach z literatury, stworzono wysoce spekulatywny model w celu sprawdzenia możliwość wpływu różnych poziomów stresu na produkcję prozdrowotnych składników przez rośliny. Symulacje modelowe wskazują, że istnieje zależność pomiędzy zadanym stresem a produkcją korzystnych dla zdrowia człowieka składników.

Anthocyanin Biosynthesis and Degradation Mechanisms in Solanaceous Vegetables: A Review

Anthocyanins are a group of polyphenolic pigments that are ubiquitously found in the plant kingdom. In plants, anthocyanins play a role not only in reproduction, by attracting pollinators and seed dispersers, but also in protection against various abiotic and biotic stresses. There is accumulating evidence that anthocyanins have health-promoting properties, which makes anthocyanin metabolism an interesting target for breeders and researchers. In this review, the state of the art knowledge concerning anthocyanins in the Solanaceous vegetables, i.e., pepper, tomato, eggplant, and potato, is discussed, including biochemistry and biological function of anthocyanins, as well as their genetic and environmental regulation. Anthocyanin accumulation is determined by the balance between biosynthesis and degradation. Although the anthocyanin biosynthetic pathway has been well-studied in Solanaceous vegetables, more research is needed on the inhibition of biosynthesis and, in particular, the anthocyanin degradation mechanisms if we want to control anthocyanin content of Solanaceous vegetables. In addition, anthocyanin metabolism is distinctly affected by environmental conditions, but the molecular regulation of these effects is poorly understood. Existing knowledge is summarized and current gaps in our understanding are highlighted and discussed, to create opportunities for the development of anthocyanin-rich crops through breeding and environmental management.