OBTAINING MAXIMUM VALUE

Transcription

1 Maximizing Post-Harvest Quality AFFLFSC 2012 Doug Waterer For all commodities, the decision to purchase is based on : OBTAINING MAXIMUM VALUE VALUE =QUALITY/PRICE As Quality increases, VALUE increases As Price decreases, VALUE increases Objective : Improving the QUALITY of crop in a manner that INCREASES its VALUE without increasing its COST Quality is in the Eye of the Beholder: To a grower : good agronomics (vigor, yields) minimal costs and risks To a Wholesaler : good market appeal commodity fits with marketing plans To the CONSUMER : right product in the right place at the right time for the right $ Indicators of Quality for Typical Consumer a) Appearance - size, colour, gloss, shape, uniformity. Freedom from blemishes. b) Feel - Texture, firmness, stringiness, crunch, density c) Flavour - ultimate reason for purchase, yet plays limited role in decision at least at supermarket Strongly influences repeat sales. d) Nutrition important but difficult to assess e) Safety - free from pesticides, human pathogens. Again difficult to determine based on appearance. Quality characteristics for. Carrots To the growers = Agronomics -cheap seed - good germination %, - good strong top - good pest resistance - early maturing and high marketable yields - store well (no shrinkage or disease) 1

2 Maintaining Post-Harvest Quality Maintaining Post-Harvest Quality Quality characteristics for. Carrots To the Seller (you or the wholesaler) Market Demand - good color. No greening. Nice trim - uniform shape and size Marketing Plans - consistency of volumes and quality - maintain quality through to point of sale. Quality characteristics for. Carrots To the Consumer - juicy with a fine texture - high sugar content - low in bitter components - good color, uniformity WANT ALL OF THE ABOVE BUT AT AS LOW A PRICE AS POSSIBLE 2) Select a cultivar that meets everybody's needs Selecting a Quality carrot cultivar Danvers -high yielding, early maturing - store and handle well - deep orange = good for processing. - tough and poor flavor when older 2) Select a cultivar that meets everybody s needs Selecting a Quality carrot cultivar Nantes - best fresh eating gq quality of all carrot - small tops and brittle = tough to machine harvest. Also are brittle - poor storage/handling potential - grown for "baby" and gourmet carrot market = $$$ 2) Select a cultivar that meets everybody s needs Selecting a Quality carrot cultivar Imperator -v. high yields + uniform shape roots - adapted to mechanical handling -store well - mid to late maturing - large core = low sugars. Tough when old. Norland vs Peregrine Red Potatoes Norland has better yields (G) Peregrine has better color (C) Norland has better disease tolerance (G) + (C) Peregrine is less prone to sprouting (C) + (G) 2

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4 3) Production practices that produce desired quality characteristics Involves; - site selection - field preparation - control of plant populations - fertility and water management - pest control etc. 3) Production practices that produce desired quality characteristics 3) Production practices that produce desired quality characteristics Producing a Quality Carrot Crop Site Selection -a cool, steady growing season = uniform growth - warm days and cool nights for maximum sugars - sandy soils = long straight roots + easy washing Field preparation - no plough pan or clods - work to 12" - bed soil=better roots and easier harvest Producing a Quality Carrot Crop Planting Timing so that reach correct size and sugar content with maximum yields by fall Plant populations - as density increases, average width decreases = more dehydration in storage Fertility High soil K levels improve sugar content = better flavor and storage 3) Production practices that produce desired quality characteristics Producing a Quality Carrot Crop Irrigation Key to getting good stand and yields Key to good appearance Key to smooth harvest What about irrigation vs. flavor + storage potential? Maintaining Post-harvest Quality 4) Harvest at optimum stage/time Proper harvest timing varies with anticipated use; For immediate local consumption... usually delay harvest until commodity is very mature = maximum sugars, weight, color change, tissue softening etc. If significant transportation or waiting period prior to sale is anticipated... mature product usually have a short post-harvest lifespan and low tolerance of handling = harvest less mature. Carrots - once the carrot is about 3 months old, total sugar content is stable = optimum eating quality. However, sucrose/monosaccharide ratio increases with time = increased storage potential. Consequently, delay harvest as long as possible. 4

5 SASKATOON FRUIT CHARACTERISTICS OPTIMUM RANGE WEIGHT SUGARS ACIDITY FIRMNESS FRUIT STAGE FROM KNOWLES ) Minimize damage at harvest Hand harvested is usually better quality - less damage to the commodity - pick crop at proper size and stage. - leave culls behind Problem accessing, training, monitoring and paying good pickers 5

6 Post-Harvest Handling Step 1. Cooling Quickly and economically cool from field temperatures to an optimal storage temperature, without affecting quality. 1) slows respiration = slows aging in storage 2) reduces moisture loss from the commodity 3) slows activity of decay organisms Maintaining Post-Harvest Quality Post-Harvest Handling Step 1. Cooling In the field 1) harvest during cool periods (daily and seasonal). 2) avoid exposure after harvest to light, wind or rain. 3) shade if possible. Tarp loads to reduce light input 4) minimize period between harvest and cooling How? Post-Harvest Cooling Systems Design Considerations : 1) building/purchase and operating costs, 2) capacity required (volume of product/time available), 3) type of container being used 4) the commodity requirements. Maximizing Post-Harvest Quality Cooling Options: 2) Forced air or pressure cooling 1) Room cooling - commodity is placed in a cold room (0-4 o C). - air flow is minimal - rate of cooling is slow hours -easiest (aka cheapest) precooling system to set up and operate. 6