Review of.. Impact of Preharvest Factors Affecting Quality and Safety of Horticultural Foods

Transcription

1 Review of.. Impact of Preharvest Factors Affecting Quality and Safety of Horticultural Foods UC Postharvest Technology of Horticultural Crops June 19, 2015 T. Suslow Dept. Plant Sciences Preharvest calcium sprays may reduce postharvest bitter pit 1 Intrinsic quality cannot be improved during postharvest management GOAL - optimal postharvest quality visual sensory nutritive attributes achieving storage potential Reaching your goal is determined or greatly influenced by preharvest events and management 2 Our topic focus. Quality factors that cannot typically be avoided, graded, or scored at harvest Preharvest internal defect; poor irrigation management or excessive rainfall Preharvest infection shows up only during storage Sunscald becomes more apparent with ripening of MG tomato3 tvsuslow@ucdavis.edu 1

2 Preharvest Factors Affecting Quality Principles underlying our expectations The interaction between variety, location, and season should not be underestimated These outcomes cannot always be predicted Fertility management can greatly impact postharvest quality - directly and indirectly Fertility management impacts postharvest decay susceptibility - directly and indirectly Crop water status can significantly determine postharvest quality and phytonutrient content Plant canopy and microclimate manipulations affects postharvest quality 4 Variety Selection: Genetics Plays a Huge Role in Postharvest Quality Breeding and selection strategies include; Best overall performance in all regions Best performer within region or season Time to maturity within a region & season Uniformity of maturity vegetative; flower; fruit 5 Role of cultivar in postharvest quality loss Example: Grape tomatoes and weight loss Cultivar Shrivel * % weight loss Ahern Amsterdam Harris LI Hazera Rotterdam TC LSD *Shrivel score -1-5 scale, 1=none, 2=slight, 3=moderate, 4=moderately severe, 5=severe days 20C 50%RH Cantwell, tvsuslow@ucdavis.edu 2

3 Environmental factors: Impact on sensory and nutrient content Examples Soil type, texture, ph Air temperature Soil temperature Light availability Light quality Field vs. glasshouse Air pollution Altitude Genetics + environment generally determine outcome 7 What caused this quality defect that showed up on >30% of packed fruit 10 days after harvest? a. Impact bruise b. Compression bruise c. Calcium deficiency (Blossom-end Rot) d. Preharvest flower infection 8 High RH and cool temperatures promote floral infections after pollination Preharvest infections may form quiescent infections that remain dormant until ripening Reduction of inhibitory compounds Cell wall disassembly release of activators and nutrients 9 tvsuslow@ucdavis.edu 3

4 Blossom scar Infection Trace Alternaria spp. 10 Specific Risk Will Differ With Variety:Environment Interactions Cool conditions and variety result in persistent stamen and involute blossom end Carrot varieties have been bred for mechanical harvest and uniform internal color 12 4

5 CARROT CRACKING - Variety is very important - Temperature is a minor factor - Cracking is increased by high N fertilization I. Imperator D. Dominator C. Cellobunch N. Nantes Cantwell, UC Davis 13 Effect of Carrot Variety and Temperature on Cracking Cracking Index (Total % carrots cracked/height when dropped 2, 3, 4 and 5 feet) Cultivar Imperator Dominator Cellobunch Nantes C 36 F 12.5 C (55 F) Temperature 20 C (68 F) Cantwell, UC Davis 14 Impact of Soil Quality and Seed Bed Preparation on Market and Sensory Quality Predisposing factors Compacted soil Sub-surface hardpan Poor foliar disease management Green Core & Green Shoulders Consequences Visual green core Non-visual bitter, soapy flavor High harvest losses 15 tvsuslow@ucdavis.edu 5

6 Why Might You See Uneven Quality in a Given Lot of Peaches? Preharvest Effects on Physiological Disorders Fruit Position on the tree Exterior vs. Interior High vs. Low Fruit-bearing wood age Pruning / canopy structure Fruit pulp temperature High N OR High Mg and K Low Ca Preharvest Genetic:Environment Influences Texture Environmental factors influence the genetically programmed development and postharvest modification of desirable and undesirable changes in texture Light intensity Fruit Pulp Temperature Water availability during development Fertility management ( N, P, K, Ca, Bo) Misapplication of growth regulators tvsuslow@ucdavis.edu 6

7 Position in Canopy Effects Mango Ripening and Texture Braz. J. Plant Physiol., 19(4): , 2007 Developmental Timing of Water Stress Effects Mango Quality Braz. J. Plant Physiol., 19(4): , 2007 Stone Fruit Ripening and Textural Quality are Strongly Affected by Preharvest Management and Environmental Conditions CAB International The Peach: Botany, Production and Uses (eds D.R. Layne and D. Bassi) 7

8 Leaf nitrogen affects % fruit surface that is red (mean for 3 years): Fantasia nectarine. a,b,c Values within columns with unlike superscript letters were significantly different by the Least Significant Difference test (P < 0.05) Impact of Environment on Postharvest Disorders and Disease Microclimate management Gray Mold (Botrytis cinerea) Leaf removal within canopy reduces RH and lowers Botrytis incidence and sporulation 23 Impact of Environment on Postharvest Disorders and Disease Prebloom orchard sanitation by mummy removal and burying reduces source of spores and Brown Rot 24 tvsuslow@ucdavis.edu 8

9 Impact of Environment on Postharvest Disorders and Disease Gold Speckles High temperature and humidity High nitrates and PO 4 Leads to calcium oxalate crystals Pierce cells; apparent on ripening Incidences > 50% Can lead to rapid decay Photo credit: J. Bartz UFL 2011 Den Outer, R.W. and W.H.L. Van Veenendaal, Gold specks in tomato fruits(lycopersicon esculentum Mill.). J. Hort. Sci., 63: Colored and Reflective mulches may improve pest control, earliness, yield and quality Including Lower soil temperature Uniform color development Thicker cuticle Compact plant structure Less lodging in wind Reflective mulch Various Methods for Increasing Light Incidence to Fruit Spray-on mulch 27 tvsuslow@ucdavis.edu 9

10 Plant health under the soil surface is the root of many postharvest disorders Good Root:Shoot Ratio Poor Root:Shoot Ratio Examples: Calcium disorders Thin fruit wall Browning potential Hollow-heart Black-heart Pith decline Blotchy-ripening Sunscald Sudden-collapse 28 Pith Breakdown of Celery a Preharvest and Postharvest Disorder Transplant Quality - Root Health Irrigation and Micronutrient Management Climate Interactions cold or hot Non-uniform maturity harvest timing decision Irrigation and Fertilization NITROGEN FERTILIZATION High N associated with excess vegetative growth High N associated with high leaf protein and pigment concentrations (chlorophyll, carotenoids) High N associated with reduced postharvest life due to increased susceptibility to decay, mechanical damage and physiological disorders 30 tvsuslow@ucdavis.edu 10

11 Excess Nitrogen Applications Interfere with Potassium Uptake Example: Tomato fruit that develop during K + stress conditions can be puffy, soft, low in acidity, irregular shaped, blotchy ripening, and susceptible to ripening-related decays 31 Wall-thickness is important for shipping quality Prevents high rates of water loss/softening Good wall thickness is inhibited by Irregular irrigation Excessive N and high temperatures Heavy fruit set (less problem with hybrids) 32 High Nitrogen Reduces Cuticle Density and Increases Water-loss Softening CUTICLE DENSITY (µg/mm 2 ) Water Loss Cuticle Density RATE OF WATER LOSS (% F.W./day) NITROGEN FERTILIZATION (lbs/ac) 33 tvsuslow@ucdavis.edu 11

12 Cuticle Thickness Influences Brown Rot Susceptibility Lower Nitrogen Higher Nitrogen 34 Differences Observed in Cuticle Roughness due to N-dose 75ppm Leaf 6 250ppm Leaf 6 Roughness Hydrophobicity E. Gutierrez et al. Intercellular spaces and cell size of spinach leaves enlarge with increments in nitrogen fertilization (Pa) 100µm (Pa) (Pa) (S M) 75ppm Leaf 6 (S M) 150ppm Leaf 6 Pa=Palisade, SM= Spongy Mesophyll 10X magnification (S M) 250ppm Leaf 6 Greater number and more enlarged intercellular spaces tvsuslow@ucdavis.edu 12

13 Surface characteristics of fresh produce and their impact on attachment and removal of human pathogens on produce surfaces Hua Wang, Bin Zhou, and Hao Feng Surface topography Surface hydrophobicity Both influence attachment and detachment Decontamination of Fresh and Minimally Processed Produce. Edited by Vicente M. Gómez-López John Wiley & Sons Confocal Laser Scanning Microscopy Reveals Surface Traits That Vary with Preharvest Management and Conditions apple avocado cantaloupe orange Wang et al Decontamination of Fresh and Minimally Processed Produce. Edited by Vicente M. Gómez-López John Wiley & Sons FRUIT DISORDERS CAUSED BY MINERAL DEFICIENCIES OR EXCESSES Boron deficiency Calcium deficiency (from Kader, 1996) malformation of stone fruits corking of apples, apricots, pears lumpy rind of citrus marking face in olives cracking of apricots bitter pit of apples blossom end rot of tomatoes, peppers and watermelons cork spot in apples and pears black-end in pears brown discoloration of apple tissue red blotch of lemon 39 13

14 Fertility Management and Phytonutrients The effects of mineral nutrition on plant phytonutrients minimally depends on 1) the nutrient 2) the nutrient form 3) the phytonutrient 4) inherent levels determined by genetics 5) irrigation practices 6) may be elevated or reduced by stress factors 40 Bioactive Compounds: Berries Fruit size in general is negatively correlated with firmness and amount of berry phenolics Fruit load N fertilization Water management Fruit bearing order has a significant effect on the bioactive compound content The phenolic content is reported to be increased by 10-25% from primary to tertiary fruits Inconsistent observation What is Fruit Bearing Order? Primary Secondary Tertiary tvsuslow@ucdavis.edu 14

15 Nitrogen applications significantly influences the level of bioactive compounds Principal Component Analysis helps identify key interacting factors N dose Conventional vs. Organic Cultivar L. Ali Pre-harvest factors affecting quality and shelflife in raspberries and blackberries (Rubus spp. L.). Summary Points 1. Maximum postharvest quality can be achieved only by understanding and managing the various roles that preharvest factors play in postharvest quality 2. Preharvest factors impact phytonutrient content and sensory volatiles 44 Take Home Lesson: Remember the Five P s 45 tvsuslow@ucdavis.edu 15

16 Preharvest Planning Prevents Postharvest Problems 46 16