The Chemical Story of Olive Oil: From Grove to Table

by Richard Blatchly, Zeynep Delen, Patricia O'Hara

Overview

Despite the growing interest in olive oil, most people know very little about what it is or how it is made. This book provides a comprehensive treatment of olive oil from the tree to table, from a molecular and personal perspective.

Growers often do not know what is happening at a molecular level or why certain practices produce superior or inferior results, for example, why adjusting a temperature rewards them with winning oils. This book aims to provide some of the answers as well as the importance of the chemicals responsible for the flavour and health effects. Readers will also get a deeper understanding of what makes an extra virgin olive oil authentic and how scientists are helping to fight fraud regarding this valuable commodity.

Including anecdotes from growers of olives and producers of oils, the authors provide an accessible text for a wide audience from food science students to readers interested in the human story of olive oil production.

Product Details

ISBN-13:	9781782628569
Publisher:	RSC
Publication date:	02/21/2017
Pages:	348
Product dimensions:	6.00(w) x 8.90(h) x 0.90(d)

Read an Excerpt

The Chemical Story of Olive Oil

From Grove to Table

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By Richard Blatchly

The Royal Society of Chemistry

Copyright © 2017 Richard Blatchly, Zeynep Delen Nircan and Patricia O'Hara
All rights reserved.
ISBN: 978-1-78262-856-9

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CHAPTER 1

Olive Origins

In this chapter, we start by outlining the history of olive trees and their important role in the development of human civilization in the Mediterranean. Ancient Greek, Roman, Jewish, Christian, and Islamic writings pay homage to the olive tree and describe how critical it is in providing food, heat, and light necessary for survival. The near immortality of the trees connects them with the ancient gods whose own immortal existence is mirrored in ancient trees such as the one shown in Figure 1.1. We will take you with us to excavations from Neolithic villages, where we can see that our ancestors used olive wood in their campfires, and to archeological sites of the bustling Bronze Age city of Klazomenai, where the pressing of olives at a communal olive press used a clever system of rock hewn holding tanks for separating the oil from the fruit liquor.

While we typically think of warm Mediterranean countries whenever olive oil is mentioned, we now understand that olives can be grown throughout the world in the "olive belt" of about 30° to 45° latitude in both the Northern and Southern hemispheres as long as the land is sufficiently dry. In places like Spain, Italy, Greece, Turkey, and Tunisia, the "Old Olive World," new commercial groves with millions of trees and modern presses stand next to family groves of several hundred trees that can be many hundreds of years old and village presses that were built at the turn of the last century. In the Mediterranean, many people either own their own groves or know someone who does. Most people who live in the country will have an olive tree or two in their garden. They may have consumed olive oil all their lives without ever having bought any! In general, consumers have very strong ideas about the way things should be done and how olive oil should taste. Modern agricultural practices can sometimes clash with the cultural olive heritage of the Old Olive World. By contrast, new groves and presses in areas like California, Australia, New Zealand, South Africa, and Argentina exist in the absence of that tradition. While some of the earliest European settlers in these former colonies brought olive trees with them, no substantial olive industry developed here until the end of the 20th Century. Today, in these "New Olive World" countries, groves of a million or more trees are harvested and transported within hours to modern facilities where they are processed using state of the art centrifugation methods. Perhaps the vision statement for the South African Olive Association "Old World Ideals with a New World Vision" best captures the contrast.

Today, it is very difficult to create quality olive oil in bulk without a team of dedicated people who plant, prune, and fertilize the trees, prepare the soil, harvest at the right time with the right equipment, deliver the fruit to the press in as timely a way as possible, process the fruit with respect for the natural goodness, bottle the oil with great care to preserve the quality and minimize degradation, perform chemical tests to ensure that the oil meets the highest standards, ship the oil according to accepted protocols, and store and sell the oil with the interests of their consumers in mind. As this book takes you through each of these stages in olive oil production, it will introduce you to a contemporary olive oil expert from around the world whose knowledge, vision, resourcefulness, and enthusiasm is emblematic of the hundreds of thousands of professionals who cooperate to bring the world's best olive oils to your tables. These individuals have helped us to understand the links between history, quality, production, and processing.

Since the soul of the oil is made from the molecules that compose it, each chapter will also feature a particular molecule or molecules that best represent the ongoing development of the olive from grove to table. We will start in this chapter with triolein, the molecule that makes up the bulk of the oil itself and then, in later chapters, introduce you to the important and unique molecules that are present in smaller quantities but are responsible for the wonderful flavors, fragrances, and health effects. Introducing these natural compounds allows us to provide a richer explanation of the techniques of growing and processing, as well as of the impact on humans such as taste and smell, and can be proven to be responsible for the many health benefits of olive oil.

Most of all, we hope the readers will finish with an appreciation for the extraordinary effort required to make a high-quality EVOO (extra virgin olive oil), an understanding of what makes a good quality oil, and an increased resolve to include more of it in their daily life.

1.1A CULTURAL LEGACY OF OLIVE TREES AND OLIVE OIL

Ancient Islamic, Judaic, and Christian texts refer to the olive tree and olive oil as sacred. Olive imagery has been captured in many cultural traditions and great writers and thinkers from Homer, Hippocrates, Columella, and Pliny all wrote of its almost magical healing and anointing properties. Mustafa Kemal Atatürk, founder and first president of the Turkish Republic, was an advocate for modern olive production. Even Thomas Jefferson, one of the founding fathers of the USA, believed in the beneficence of the olive tree. Let's see what has been said about the origins of the olive tree and the utilization of its wonderful oil in and out of the kitchens of our forefathers.

1.1.1 An Olive Tree is "... a Covenant Between God and His People"

The first origin story for the olive tree comes to us from the early Judeo–Christian tradition as documented in the 1st Century manuscript on the Penitence of Adam from the Vita Adam. At the end of his life, Adam sent his third son Seth back to the Garden of Paradise to request the oil of divine mercy promised to him by God for his own redemption and that of humanity. Instead, the Angel guarding the gate gave Seth three seeds from the Tree of Life (or the Tree of Knowledge). Instructions were given to put the seeds in Adam's mouth upon his death and bury them along with his body. When the time came and Adam died, Seth followed the Angel's instructions and buried his father along with the seeds. A short time later, three saplings (or one tree with three branches) grew from the burial site. Though texts differ on the eventual destiny for the tree(s) at least one story has the trees growing into a cypress, a cedar, and an olive tree – three classic trees of the Middle East. According to one 15th Century text, the wood from these sacred trees grown out of the flesh and bones of Adam later become the rod of Moses and the cross on which Jesus was crucified. Figure 1.2 captures images of this story of the origins of these three trees from a 15th Century Italian fresco, a 15th Century Dutch woodcut and a modern photographic installation in Israel.

So, the olive tree appears as a gift from God to these humans, and represents a promise of his mercy and steadfast love. The Old Testament of the Christian bible makes more than 100 references to olive trees, olive oil, and olive branches. Perhaps most familiar is the olive branch brought back by a dove to the Ark and given to Noah to let him know that the floodwaters had receded (Genesis 8:11). With the branch came a promise – a covenant – that God would never again repeat this total destruction.

The use of olive oil for religious anointing is a frequent reference as is its use as a source of light against the darkness.

"And thou shalt command the children of Israel, that they bring thee pure oil of the beaten olive for the light, to cause the lamp to burn always." Exodus 27:20

The New Testament holds a similar symbolic importance for the olive tree. On the night before he died, Christ retreated with his disciples to the Mount of Olives and was later captured close to the local olive press at Gethsemane (Mark 14:26–32). In Romans 11:17–24, the apostle Paul discusses grafting of wild saplings onto strong olive root stock and uses this as a metaphor for God's cultivation of his people, seeking always the fruit of kindness.

1.1.2 An Olive Tree is "... a Gift of the Goddess Athena"

Greek mythology contains another version of the origin of the olive tree. Here, it is linked to the warrior goddess Athena, daughter of Zeus. The legend speaks of a contest designed by Zeus to be held for the gods. Each contestant was to prepare a special gift for the people of a city in Greece and the inhabitants of that city would review the offerings and choose the most perfect gift. The god who designed this gift would in turn be honored by having the city bear his or her name – thus guaranteeing the devotion and loyalty of its inhabitants for all times. On the day of the contest, two gods presented their gifts to the people of the city. First, Poseidon, god of the sea, struck the ground with his trident and out of the earth sprang a horse (some versions say a fountain). Next, Athena used her spear to strike the earth and the first olive tree instantly sprang forth. Since the olive tree was capable of producing light, heat, food, and shelter, the inhabitants of the city chose Athena's gift. The city, Athens, bears her name even to this day. Figure 1.3 shows a photograph from the Parthenon in Athens depicting the contest for naming rights to the ancient city. An olive tree which, like its creator, is (nearly) immortal stands close to the corner of the Parthenon today.

1.1.3 Olive Oil is "... Liquid Gold" Homer ~800 BCE Olive oil was a staple in Greek households and in their imaginations. More than 20 references are made to olive related items in Homer's work. In The Iliad, he describes some of its non-culinary uses. It was a critical ingredient in the goddess Hera's toilette as she set about preparing herself for her husband Zeus. Meanwhile Aphrodite anointed the body of the slain Trojan warrior prince Hector with scented olive oil. The Odyssey also contains references to olive oil's place as a treasure to be stored with gold and bronze. Perhaps most poignant is Homer's description of the wedding bed made by Odysseus for his beloved Penelope. One leg of the bed is made from a living olive tree, symbolizing perhaps their steadfast and timeless love. In a clever device to test the returning Odysseus – gone for 20 years – Penelope loudly orders a servant to move the bed to ready it for the man claiming to be her husband. When Odysseus shouts out that the bed cannot be moved because it is made of a live tree, Penelope knows the man standing in front of her is truly her long lost husband and they are joyfully reunited.

1.1.4 Olive Oil is "... the Great Healer" Hippocrates ~400 BCE

Hippocrates believed that olive oil was "the great healer." He was aware that a topical application of the oil would help relieve pain from skin abrasions and burns and he recommended it be massaged into wounds to help them heal quickly. Extracts of plants steeped in olive oil were used to provide relief from many gynecological diseases, and its use was recommended in curing infections of the ear, nose, and throat. Olive oil itself was massaged into aching muscles and its ingestion was recommended in small quantities to settle an upset stomach and in larger quantities as an emetic. Plants from celery to fennel to St John's Wort to juniper were steeped in olive oil and used to preserve youthful healthy skin.

1.1.5 An Olive Tree is "... the Chief of All Trees" Columella ~50 AD

Columella was a naturalist writer of Roman times whose complete work was thought to be lost to time until a 12 volume combined encyclopedia De Re Rustica was found in the library of a Swiss monastery in the 15th Century. Book 7 contains thorough instructions for olive trees with regard to the ground soil preparation, grove locations, pruning, and fertilizing. A complete description of how and when to press olives is given in Book 12, Chapter 50.

"As soon as the berries shall begin to be of different colors, and some of them are already black, yet more of them white (sic), the olive must be gathered by hand when the weather is fair and sifted and cleansed upon mats or reeds spread under them: after they are cleansed, they must be presently carried to the place where the presses stand, and shut up entirely in new frails, and put under the presses, that they may be squeezed as little a while as can be."

Today, these words would be precisely the same instructions given to an olive farmer who desires to make the highest quality extra virgin olive oil. Pick when the olives are partly turned, be gentle with the fruit, and get the fruit to the press as soon as possible.

1.1.6 Olive Oil is "... Common and Universal" Pliny ~70 AD

Pliny the Elder, the prolific 1st Century Roman writer, spends much ink describing the best methods for the cultivation of olive trees, the pressing of olive oil, and the many medical uses of the olive oil itself. His contrast of olive oil and wine is quite insightful.

"It is not with olive oil as it is with wine, for by age it acquires a bad flavor and at the end of a year, it is already old. This, if rightly understood, is a wise provision on the part of Nature: wine, which is only produced for the drunkard, she has seen no necessity for us to use when new. Indeed by the fine flavor which it acquires with age, she rather invites us to keep it. But on the other hand, she has not willed that we should be thus sparing of oil, and so has rendered its use common and universal by the very necessity there is of using it while fresh." (Book XV, Chapter 3, pp. 16–17.)

Pliny also repeatedly recommends: "Do not shake and beat your trees. Gathering by hand each year ensures a good harvest."

1.1.7 An Olive Oil is from a "... Blessed Tree." Qur'an 600 AD

In the Angel Gabriel's revelations to the Prophet Mohammed, the majesty of Allah is said to be like a light that burns, as in Figure 1.4, from the oil of the blessed olive tree. Unlike that oil, Allah needs no fire to provide illumination.

"Allah is the Light of the heavens and the earth. The example of His light is like a niche within which is a lamp, the lamp is within glass, the glass as if it were a pearly [white] star lit from [the oil of] a blessed olive tree, neither of the east nor of the west, whose oil would almost glow even if untouched by fire. Light upon light." (Chapter 24, Verse 35.)

This verse has been much analyzed by great Islamic philosophers such as Razi (ibn Zakariya al-Razi) in the 9th Century and Avicenna (ibn Sina) in the 11th Century. Their ideas about divine illumination, "Light upon light," and the majesty of Allah use this text as a touchstone.

Dimitri Gutas, Professor of Arabic and Graeco-Arabic at Yale University, has pointed out to us how important scholars of the Islamic golden age between the 10th and 14th Centuries, such as Avicenna and Ibn Qayyim al-Jawziyya, refer to earlier pharmacological knowledge of the time about the importance of olive oil. After referring to the verse above, they write: "Eat olive oil and anoint yourselves with it, for it is from a blessed tree." The ascription of these recommendations to the Prophet Mohammed makes the advice much more authoritative in the eyes of Muslims.

(Continues...)

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Excerpted from The Chemical Story of Olive Oil by Richard Blatchly. Copyright © 2017 Richard Blatchly, Zeynep Delen Nircan and Patricia O'Hara. Excerpted by permission of The Royal Society of Chemistry.
All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
Excerpts are provided by Dial-A-Book Inc. solely for the personal use of visitors to this web site.

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Table of Contents

Olive Origins; The Beginning of a Grove: Planting the Trees; The Tree Through the Year; Season's End: Harvesting the Fruit; Processing: The Most Important Hour; Delivering Quality and Assuring Authenticity; Good Taste is Required; Health Effects: But is Olive Oil Good for You?; 1001 Uses for Olive Oil; Sustainability