Olives

Olive Production Manual

Louise Ferguson, G. Steven Sibbett, and George C. Martin

Classification

• Family - Oleaceae

–Genera

• Fraxinus (ash)

• Ligustrum (privet)

• Syringa (lilac)

•Olea (olive)

Olea europaea

• Long lived evergreen trees

• Wood resists decay

• Top dies - stock sprouts

• Roots only 3 - 4 ft (1 m) deep

• Dense foliage, poor light penetration, cascading multiple branches, heavy fruit on terminals

Leaves

• Thick, leathery, oppositely arranged

• Each leaf grows for 2 yrs

–Spring abscission in 2 to 3 years

• Stomata on lower surface only

–nestled in peltate trichomes

Cultivars

• Ascolano 9 gm / 18.8% Blk Grn

• Manzanillo 5 gm / 20% Fr, Blk, Oil

• Sevillano 13.5 gm / 14.4% Blk, Grn, SpGm

• Barouni 7.4 gm / 16.5% Fr Blk

• Mission 4.1 gm / 21.8% Blk Gr Oil

Manzanillo

• Most widely planted

• Most popular for canning

• Low spreading 15 - 30 ft.

• Rooted Stem cuttings

• Not tolerant to cold

• Olive knot - Verticillium wilt

Sevillano

• Second most popular

• Spreading 25 - 35 ft tall

• Trained low for easy harvest

• Largest fruit in California

• Grafting 1 yr rooted cuttings

• Somewhat resistant to cold

• Bruises easily

Ascolana

• Rounded shape 20 - 30 ft tall

• Bruises easily

• Only 3 % of acreage in CA

• Canned ripe olives

• Fairly resistant to olive knot

Mission

• From Mexico in 1769, not Italy

• Tall upright, 40 - 50 ft

• Topped to facilitate harvest

• Small, low 6.5 : 1 fruit-to-pit ratio

• Rooted cuttings

• Trees survive 8oF

Mission Harvest

• Picked green - Spanish Green Processing because they are late and need to avoid frost.

• Red coloration - Ripe olive processin

• For oil because of high (21.8% oil)

• High monounsaturated fatty acid

Barouni

• From Tunisia in 1905

• Small tree 15 - 25 ft. spreading

• Large fruit, low fruit to pit ratio

• Resistant to cold

• For fresh use - process quality low

• Used for black-ripe table olives

Flowering

• Summer 2000 - Induction in veg buds

• Nov. 2000 - Floral induction

• Winter 2000 / 2001 - Chilling

• Spring 2001 - Flowers open

Chilling is Critical

• Optimum Flowering if chilling temps

–Maximum 60 to 65oF

–Minimum 35 to 40oF

• Poor flowering if

–Constant 55oF

• No flowering if

–No temp > 45oF or < 60oF

Influence of Leaves

• Very little dormancy

–Veg. Buds grow at or > 70oF

• Inflorescence formation

–Requires leaves on fruiting shoots

–Thus, prevent defoliation

•Hot winds can defoliate

Flower Buds

• Abnormally cold spring temps

–Detrimental to flower buds

• Floral differentiation 8 - 10 weeks before May bloom

– Irrigate to prevent stress

–Start season with moist profile

• Playing catch up will not do

Stress

• Causes predominance

–Of male flowers

–Why?

• Girdling can increase flowering

–Danger of Olive Knot

–Not a problem in Israel

–Root reduction

Pollination

• Monoecious

• Flowers borne axially along shoot in panicles

• Self and cross pollination occurs

Fruit Set

• 500,000 flowers per tree

• Need maximum of 10,000 fruit (2%)

–98% abscise in 14 days

–Goal is 3 tons per acre yield

• Sometimes insufficient perfect flowers to set full crop

• Need 10% set if inflorescence limited

Fruit Formation

• Embryo development

• Mature ovule (seed)

• Mature ovary (fruit)

• Requires rapid pollen growth

–Delays caused by cool temperature

• Parthenocarpic fruit (shotberries)

Sigmoidal Fruit Growth

• Endocarp (pit) enlarges to full size and hardens in 6 weeks

• Endosperm (liquid to solid)

• Embryo development

• Embryo maturity (September)

Maturation

• Gradual growth

–Mesocarp (flesh)

–Exocarp (skin and peel)

• Color change (harvest index)

–Green straw (optimal) Red (maybe) Black (unacceptable)

Harvesting

• Profit or loss depends on accuracy of harvest in October

• Delaying harvest = heavier fruit (more valuable)

• Delaying too long = black fruit & frost damage

• Oil content increases in January

Fruit Thinning to Avoid Alternate Bearing

• Hand thinning

–Both hands - heavy rubber gloves

–Strip fruit while leaving leaves

• Leave 6 fruit / foot of twig

• Complete 3 weeks after full bloom

• Effective but not cost effective

Thinning by Pruning

• Prune more heavily on “on” years

• Prune more lightly on “off” years

• However, not cost effective

Chemical Thinning

• NAA effective but must treat prior to knowledge of crop size

• Treat 12-18 days after full bloom (FB)

• Apply 10 ppm for each day after FB

–15 days after FB = 150 ppm

–Dilute spray (300 - 400 gal water per acre

Thinning Ornamental Olives

• Olives in landscape are more desirable if all the fruit are removed

• Use 200 ppm 2-3 days before FB

–Use second spray 1 week later

• Large trees require power sprayer

–10 - 15 gal per tree

• Detrimental if temperature > 100oF

Processing Olives

• Types

–Black-ripe (BR) - 99% in CA

–California-style green

–Spanish-style green (<1%)

• Pickling - process of adding lactic or acetic acid

Chemical Composition of Ripe Mission Olives (%)

• Water 55.0

• Brix 13.1

• Oil 21.4

• Sugars 4.6

• Protein 1.7

• Mannitol 4.4

Oleuropein

• A glucoside (bitter factor in fresh olives)

• Destroyed by dilute alkali at room temperature

• Remove alkali (1 - 2% lye) and bitterness does not return

Pigments

• Anthocyanins are major pigment

• Increases until fruit is ripe

• Decreases in overripened fruit

• Light increases formation

• 10 times more anthocyanin in fruit ripened in light vs dark

Salt Free Storage

• Acidulant solution

–0.67% lactic acid

–1.00% acetic acid

–0.30% sodium benzolate

–0.30% potassium sorbate

Traditional Brine System

• Concrete or wooden tanks

• Capacity - 20 tons

• 5.0 - 7.5% NaCl

–20 - 30o Salometer

–Saturated solution - 26.5% salt = 100o on Salometer

Storage Containers

• Open-top redwood tanks 5x6 ft

• Holds 2.5 tons of olives

• Polyethylene 6 mil plastic prevents contact between olives and inside of tank

• No fermentation in this system

• Flavor better than in brine

California Style Black Olives

• Paraffin or plastic lined 20 T tank

• Four overhead pipes

–Water

–Dilute dye

–Dilute brine

–Compressed air

Lye (NaOH) Treatment

• 3 - 5 applications of 0.5 - 1.5%

• Better color by

–Reducing lye concentration

– Increasing treatment numbers

–Reducing duration

Color Formation

• Lye helps

–Natural phenolic compounds to oxidize and polymerize

–Causing formation of black pigment

–Provided aeration is present

Calcium Helps Fix Color

• Color formation most rapid at 8.0 to 9.5 pH

• Retention better in hard water

• Ca(Cl)2 (0.1 - 0.5%) improves color retention

Lye Removal

• Lye removed by changing water in tanks at least twice daily

• Solution stirred frequently with paddles of compressed air

• Lye removed in 3 - 4 days

Canning

• 7.0 - 7.5 pH at time of canning retains color

• Packed in C-enamel lined cans

• Filled with 2 - 2.5 % salt brine

• Cans exhausted at 199 to 205oF for 5 min to reach 170oF or higher

Finish Canning

• Rebrined and sealed at 170oF in a double seamer

• Olives in glass containers processed in retort for 70 min. at 240oF

Spanish-Style Pickled Green Olives

• Fruit reaches full size but harvested before color changes

• Promptly placed in shallow paraffin - or plastic-coated concrete pickling vats

Lye Treatment

• Dilute lye (1.25 - 1.75%) at 54 - 70oF penetrates 3/4 way to pit in 8 - 12 hrs.

• Small amt of untreated bitter flesh characteristic of green olives

• 1 drop of phenolphthalein to cut surface shows depth of lye penetration

Post Lye Treatment

• Olives washed in cold H2O 24-36 hrs

• Water changed every 4 - 6 hrs

• Then response to indicator very faint

Fermentation

• Washed, lye-treated olives transferred to 50 gal oak barrels

• Head replaced and hoops driven

• 11% brine added through side bung

–Lactic acid content 0.8 - 1.2%

–3.8 pH or less

• Fermentation at 75 - 80oF for 1-12 mo

Producing Olive Oil

• Spain, Italy, and Greece (in that order) produce 80% of world’s oil

• They consume 75%

• USA < 1% of world’s olive oil

• International Olive Oil Agreement

• Administered by International Olive Oil Council in Madrid, Spain

Fatty Acid Profile

• Oil Saturated Unsaturated

• Mono Poly

• Olive 1st CP 3 88 9

• Olive 2nd CP 11 83 5

• Pecan C P 9 73 18

• Cardin Pecan 5 85 10

• Walnut EP 9 18 73

• CP = Cold Pressed, EP= Expeller Pr

Definition of Olive Oil

• Olive oil - obtained solely from olives

• Excludes oil extracted by solvents or reesterification processes, or any mixtures with other oils

• Pure olive oil cannot be any olive residue oils

Virgin Oil

• Mechanically pressed from olive fruit without using heat - cold pressing

• Only washed, decantation, and centrifugation (natural product)

• May have vintage years on label

Grades of Virgin Oil

• Virgin Olive Oil Extra

–Extra Vergine (Italian)

–Vierge Extra (French)

• Pure unadulterated oil from top quality olives

• Perfect taste and odor

• Max of 1% acid and strong odors

Other Olive Oils

• Virgin Olive Oil Fine or Fino

–Almost perfect taste but 1.5% acid

• Semi-fine or Ordinary Olive Oil

–Good taste maximum acidity 3.3%

• Virgin Olive Oil Lampante > 3.3%

–Not for human consumption

Poorer Grades

• Refined oils

–Caustic soda used to purify virgin oil from cull fruits

• Blended oil

–Blend of refined and virgin oil

–Most imported olive oil in USA

Residue Oil

• Olive-residue oil obtained by treating pomace with solvents

THE END