FARMSOFT FRESH PRODUCE QUALITY control & QUALITY CONTROL
Farmsoft QC Quality control app makes fresh produce quality control rapid and accurate for all fresh produce packers: cherry, berry, onion, pepper & capsicum, avocado, potato quality, broccoli, salad quality control, spinach, lettuce, cucumber, tomato quality, citrus, asparagus, garlic quality control app, carrot quality, bean, mango, leafy greens, fresh cut quality control, food service quality app, coleslaw quality, strawberry quality control app, grape quality, meat quality control app, flower quality.
SPINACH STORAGE FOR QUALITY MANAGEMENT
Spinach, Spinacia oleracea L. (2n = 12), is an important leafy vegetable, of which the leaves and tender shoots are consumed fresh or processed. Spinach is native to central Asia, most probably Persia (Iran). Spinach (Spinacia oleracea L.) belongs to the family Chenopodiaceae. Spinach is annual for leaf production and biennial for seed production. It produces rosettes of fleshy leaves, which may be crinkled or smooth in the vegetative phase; later, the stem elongates and forms flower stalks during the reproductive phase, with narrow, pointed leaves. This chapter discusses the cytology and genetics of spinach. Spinacia oleracea L. contains 2n = 12 chromosomes. Sex expression in spinach is controlled by a single pair of sex chromosomes (XY). The main objectives of spinach improvement are high yield, good quality of green leaf, uniformity, and resistance to major diseases. Breeding methods applicable to the improvement of cross-fertilizing vegetable crops may also be applicable to spinach improvement. Population improvement methods such as recurrent selection, mass selection, and progeny testing are suitable for the development of new variation. The chapter discusses the objectives for breeding spinach and the breeding methods used in the breeding of this vegetable.
Spinach, Spinacia oleracea L. (2n = 12), is an important leafy vegetable, of which the leaves and tender shoots are consumed fresh or processed. Spinach is native to central Asia, most probably Persia (Iran). Spinach (Spinacia oleracea L.) belongs to the family Chenopodiaceae. Spinach is annual for leaf production and biennial for seed production. It produces rosettes of fleshy leaves, which may be crinkled or smooth in the vegetative phase; later, the stem elongates and forms flower stalks during the reproductive phase, with narrow, pointed leaves. This chapter discusses the cytology and genetics of spinach. Spinacia oleracea L. contains 2n = 12 chromosomes. Sex expression in spinach is controlled by a single pair of sex chromosomes (XY). The main objectives of spinach improvement are high yield, good quality of green leaf, uniformity, and resistance to major diseases. Breeding methods applicable to the improvement of cross-fertilizing vegetable crops may also be applicable to spinach improvement. Population improvement methods such as recurrent selection, mass selection, and progeny testing are suitable for the development of new variation. The chapter discusses the objectives for breeding spinach and the breeding methods used in the breeding of this vegetable.
QUALITY CHANGES DURING STORAGE OF SPINACH AND LETTUCE BABY LEAF
Spinach and lettuce are important vegetable products in the minimally processed leafy vegetables industry. The quality parameters of these products are represented by leaf pigments that affect the visual appearance and by internal quality components such as ascorbic acid, carotenoids and phenols. Storage experiments were performed on leafy vegetables harvested at commercial stage and stored at 4 or 10°C. The content of ascorbic acid, chlorophyll, carotenoids and phenols were determined at the beginning of the experiment and after 6 days of storage. Ethylene accumulation was also measured. Results obtained showed that chlorophyll, carotenoids and phenols did not change in both species after 6 days of storage at both temperatures. Ascorbic acid declined during storage. The decrease was more pronounced in lettuce than in spinach. In lettuce ascorbic acid content was below 0,5 mg/100 g FW after 6 days of storage, at both storage temperatures. In spinach ascorbic acid decreased in leaves stored at both temperatures, but at higher temperature (10°C) the degradation process was faster. Ethylene levels after 6 days of storage were below 0.1 µl L-1 in bags of spinach. In the case of lettuce, ethylene levels after storage were about 1 µl L-1. Even if some quality parameters are stable during the 6 days of storage, the decline of ascorbic acid suggests, at least for lettuce, a fast commercialisation and a correct cold chain for the best health benefit.
SPINACH QUALITY control PROCESS
Prediction of Spinach Quality Based on Pre- and Postharvest Conditions E. Gutiérrez-Rodríguez, J.H. Lieth, J.A. Jernstedt and T.V. Suslow Department of Plant Sciences University of California Davis, CA 95616 USA Keywords: spinach, nitrogen, organic acids, ammonium, glutamine synthetase, storage Abstract Nitrogen amendments and water availability have a significant effect on the nutritional quality of spinach. Despite this established knowledge, the specific influence of these interacting factors on overall postharvest quality is poorly under-stood. Determined by interviews with multiple growers, current agronomic practices in California and Arizona routinely include the application of 100 to 350 kg/ha total N. Preharvest trials and postharvest evaluations with field and hydroponically-grown spinach were conducted to elucidate how this fertility management practice influences quality. Additionally, quantitative evaluations were performed to identify predictors of market quality at harvest and during storage. Preharvest nitrogen availability greater than 100 ppm coupled with high temperature during cultivation reduced the overall quality of spinach. Color (hue) of spinach grown under various N rates and stored at 7.5°C (in perforated polymer-film packaging) did not reliably predict the key phyto-nutrient composition and marketable shelf life. Marketable shelf life was initially defined as a combination of visual quality score (OVQ) ≥6.5 (on a 9 point hedonic scale), decay <1%, and ascorbic acid concentrations ≥35 mg/100 g FW. Ammonium accumulation more reliably anticipated the reduction of quality during storage than other parameters taken as single assessment indicators. Changes in respiration rates, chlorophyll and carotenoid concentrations during storage were poor indicators of marketable shelf life. More accurate quality retention projections were achieved by combining ammonium concentrations with measurements of glutamine synthetase (GS) activity at harvest. Total organic acids (TOA) and sugar content >3.5 mg/g FW at harvest were negatively associated with quality retention. Although storage tempera-tures significantly affect quality retention in spinach, the initial quality at harvest is the main factor that influences inherent postharvest potential. Spinach pre- and postharvest quality is best predicted by analysis of TOA, sugar concentrations and the relationship between ammonium and GS at harvest while during storage OVQ, TOA and ammonium concentrations were practical descriptors of marketable shelf life. INTRODUCTION Postharvest management for spinach focuses mainly on temperature control and water loss. Because of its high respiration rates (40-70 ml CO2/kg-h at 10°C) and its high sensitivity to ethylene and elevated CO2 concentrations, spinach needs to be cooled in an expedited manner soon after harvest (Suslow and Cantwell, 2009). Once spinach has been packaged, high oxygen and low carbon dioxide concentrations at temperatures close to 0°C favor high spinach quality (Cantwell et al., 1998; Suslow and Cantwell, 2009). There have been several attempts to describe the postharvest quality of spinach during storage at different temperatures based on color and visual quality measurements as well as chlorophyll, and carotenoid content. Although reproducible results were described, the marked differences in storage temperatures were the driving factor in the quality assessments reported. The objective of this study was to characterize those quality assessments at harvest that could predict the postharvest quality of spinach during storage associated with N fertilization.
SPINACH QUALITY CHECKLIST
Spinach and lettuce are important vegetable products in the minimally processed leafy vegetables industry. The quality parameters of these products are represented by leaf pigments that affect the visual appearance and by internal quality components such as ascorbic acid, carotenoids and phenols. Storage experiments were performed on leafy vegetables harvested at commercial stage and stored at 4 or 10°C. The content of ascorbic acid, chlorophyll, carotenoids and phenols were determined at the beginning of the experiment and after 6 days of storage. Ethylene accumulation was also measured. Results obtained showed that chlorophyll, carotenoids and phenols did not change in both species after 6 days of storage at both temperatures. Ascorbic acid declined during storage. The decrease was more pronounced in lettuce than in spinach. In lettuce ascorbic acid content was below 0,5 mg/100 g FW after 6 days of storage, at both storage temperatures. In spinach ascorbic acid decreased in leaves stored at both temperatures, but at higher temperature (10°C) the degradation process was faster. Ethylene levels after 6 days of storage were below 0.1 μl L-1 in bags of spinach. In the case of lettuce, ethylene levels after storage were about 1 μl L-1. Even if some quality parameters are stable during the 6 days of storage, the decline of ascorbic acid suggests, at least for lettuce, a fast commercialisation and a correct cold chain for the best health benefit.
SPINACH QUALITY SYSTEMS
SPINACH PACKING, SPINACIA OLERACEA / CHENOPODIACEAE
Postharvest Atmosphere Management
It is recommended to market spinach immediately, although they can be stored at temperatures of 0ºC and moisture over 95% for a period of two weeks, which are extended to four weeks if the produce is of good quality and the environmental conditions are strict.
Spinach benefit from fast pre-cooling, that diminishes its metabolic activity and increases preservation. The temperature must be preferably of 0ºC. With pre-cooling and packaging in plastic bags the storage may last up to 40 days.
Cool storage around 0-(-1ºC) and 90-95% of relative moisture enables the produce to last between 2 and 4 weeks. It is extremely important to maintain high levels of relative moisture during the storage of loose leaves, that is to say, unwrapped produce. When plastic protections are used, the environment inside the plastic bag has a high level of relative moisture
Controlled atmospheres adding 10-20% of carbon dioxide have only a slight effect in preservation and they are not used at commercial level. It has been proved that the addition of 10% of carbon dioxide prevents yellowness and increases in one week the storage of spinach, with a temperature of conservation around 5ºC. Plastic films have been chosen to package pre-washed spinach leaves kept at 1-3% of oxygen and 8-10% of carbon dioxide.
Distribution
Transport must be carried out at low temperatures, between 0 and 5ºC, and high environmental moisture. The maximum temperature recommended when loading is 6ºC, for no longer than 3 days.
During distribution the levels of moisture must be high, in order to avoid drying, and the temperature must not exceed 10ºC.
Postharvest Problems
The metabolic activity of spinach is one of the highest among the leafy vegetables. It is a determining factor of its brief post-harvest life, that hardly surpasses 12 days.
After the harvesting of spinach, arises a series of changes that may deteriorate the quality. The most frequent are: dehydration, yellowness, changes taste, compositional changes and diseases caused by blight and loss.
Spinach Dehydration
The loss of water causes the blight of the produce and therefore, the loss of the fresh appearance. Plastic protections reduce this problem.
Spinach Yellowness
The degradation of spinach chlorophyll is a process associated to senescence having as a consequence the yellowing of the leaves, an undesired phenomenon occurring in leafy vegetables.
The lesser amount of leaf spinach losses of chlorophyll take place at 10ºC, and there are not many differences between wrapped and unwrapped spinach. At 20ºC the treatments with plastic are those that maintain the best spinach colour.
Compositional changes
During the post-harvest there is a series of compositional changes among which are the diminution of ascorbic acid (vitamin C), proteins and the increase of thiamin (vitamin B1)
Low temperatures slow down these modifications. It seems that the loss of water acts as an accelerator of vitamin degradation.
Spinach Diseases
- Humid rot: It is caused by the bacterium Erwinia carotovora, being the main disease of harvested spinach. The tissues affected have a watery appearance and a dirty green colour. There is a softening of the leaves and an unpleasant smell. Low humid air stops the disease, and the tissues dry and become fragile.
- Powdery mildew: It manifests during production. It is caused by the fungus Peronospora spinaciae. In spinach coming from affected fields the fungus may develop during transport and the marketing stage. The leaves show some areas with a whitish powder.
- Grey rot. The fungus causing this disease is Botrytis and it affects many other species.