RESPIRATION:

Basic mechanisms, factors affecting, measurement

PROGRAM STUDI S2 TEKNOLOGI PASCAPANENDEPARTEMEN TEKNIK MESIN DAN BIOSISTEM

INSTITUT PERTANIAN BOGOR2013

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Oleh: Dr.Ir. Rokhani Hasbullah, MSi.

Materi Kuliah

TEKNIK PASCAPANEN TANAMAN HORTIKULTURA

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Basic Mechanisms of Respiration

The term of respiration: ... the physical and chemical

processes by which an organism supplies its cells and

tissues with the oxygen needed for metabolism and relieves

them of the carbon dioxide produced in energy-producing

reactions... (Webster).

Biochemists ... Any of various energy-yielding oxidative reactions in living matter...

Respiration is a vital process to humans and other animals.

It is equally important to plant cells and tissues.

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Respiration The electrical analogy

The metabolic process in living cells is the high energy

stored in the third phosphate bond of adenosine triphosphate

(ATP).

ATP in the cell ===> rechargeable batteries

Batteries contain energy can be liberated to flashlights, radio, tape recorder, etc.

Unlike batteries, without which our lives would continue

(although much changed), a continued supply of ATP is

absolutely vital to the fundamental processes of life.

Maintaining the supply of ATP is the primary purpose of

respiration.

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Electricity generation

A model for cell respiration

Cell respiration

The TCA cycle furnace (Krebs cycle) must be supplied with a specific molecular fuel, acetyl CoA. by the process of glycolysis (sugar splitting)

5 Oksigen akan digunakan untuk mensintesis energi

ATP dalam respirasi aerob.

Pada sel, terjadi dalam mitokondria

NADH = the spark

fuel = glucose

exhaust =carbon dioxide

air = oxygen

OUTPUTengine heat= body heat

INPUT

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A key enzyme in this process is phospho-fructokinase

(PFK), a multicomponent enzyme which converts

fructose-6-phosphate into fructose-1,6-diphosphate,

thereby preparing the hexose for cleavage into 2 triose

phosphate compounds, glyceraldehyde-3-phosphate and

dihydroxyacetone phosphate.

The powerhouse of the cell mitochondrion

Contains nucleic acids

and ribosomes for synthesis protein and

enzymes.

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Acetyl-CoA

Oxaloacetate Citrate

Malate Aconitate

Fumarate Isocitrate

Succinate

-Ketoglutarate

Succinyl-CoA

H2O

CO 2

TCA Cycle

CoACO 2

CO 2

O2ADP+P

ATP

Pyruvate

Starch

Glucose-1-P

Glucose-6-P

Fructose-6-P

Fructose-1,6-diP

Phosphoglyceraldehyde

Phosphoenolpyruvate

3-Phosphoglycerate

1,3-Diphosphoglycerate

2-Phosphoglycerate

Lactate

Acetaldehyde

Ethanol

CO 2

Fermentation

The Krebs (TCA) cycle

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The basic chemistry of the process, in which the oxidation of

glucose is coupled to regeneration of ATP from ADP

(adenosine monophosphate) and Pi (inorganic phosphate)

with the release of H2O and O2 is:

C6H12O6 + 6O2 + 38 ADP + 38Pi => 6CO2 + 44 H2O + 38 ATP

Respiration is a process whereby the free energy locked up in glucose is used to generate a membrane potential by oxidising the glucose molecule to CO2 and H2O.

This membrane potential is used directly to replenish the cells supply of ATP.

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In the Generator:

The energy produced by fuel combustion is absorbed in

a heat exchanger where water is converted to high

pressure steam.

Steam becomes the energy resource.

In the Respiration:

Oxidation implies the loss of electrons from the fuel

molecule and their donation to an electron acceptor,

which is thereby reduced.

Low energy Nicotinamide adenine dinucleotide (NAD)

is reduced to the high energy form, NADH, thus:

NAD+ + H+ + 2e (from the fuel) NADH

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The electron transport system

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Concentration of ATP remains constant at all times. The net

effect of respiration can be considered to be the oxidation of

glucose to CO2 and H2O with the liberation of energy:

C6H12O6 + 6 O2 + 6 H2O => 6 CO2 + 12 H2O + 673 Kcal

Fase Respirasi

Polisakarida gula sederhana

Gula sederhana asam piruvat

Asam piruvat karbon dioksida + as organik lainnya

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Glucose+

CellularRespiration

Glucose+

+

+

Respirasi

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Perubahan yang terjadi pada produk akibat respirasi

setelah dipanen

Perombakan klorofil dan pembentukan karotenoid (warna hijau menjadi kuning/jingga)

Pelepasan etilen (menjadi agen pemicu proses pematangan shg buah akan menjadi matang)

Perombakan karbohydrat menjadi gula (rasa menjadi manis) Pembentukan zat-zat volatil (menimbulkan aroma buah

matang)

Penguapan air dan pelepasan panas

Bila tidak segera dikonsumsi perubahan akan terus

terjadi dan menjadi proses pembusukan

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Faktor-faktor yang mempengaruhi respirasi

1. Internal factors

a. Genotype (Type of commodity)

b. Type of plant part

c. Stage of development at harvest

d. Respiratory substrat

e. Preharvest factor

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Laju respirasi produk hortikultura pada suhu 5 C

Respirasi

(mg CO2/kg-jam)

Rendah 5 - 10 apel, jeruk, anggur, melon, pepaya, nanas

bw putih, bw merah, kentang, ubi jalar

Sedang 10 -20 pisang, mangga, chery, peach, pear, kubis

wortel, ketimun, batang selada, tomat

Tinggi 20 - 40 alpukat, bunga kol, daun selada

Sangat tinggi 40 - 60 brokoli, okra bunga potong

Paling tinggi > 60 asparagus, jamur, bayam, jagung manis,

jagung muda

Kelompok Komoditas

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Jenis komoditi

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umbi

batang

Buah/bunga

daun

tunasRespirasi paling tinggi

Respirasi paling rendah

Asal dari produk menentukan sifatnya

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Perubahan fisiko-kimia

(1) Fase pembelahan sel (cell division) danpembesaran sel (cell enlargement)

(2) Fase pendewasaan (maturation)

(3) Fase pematangan (ripening)

(4) Fase pelayuan (senescence) dan diikuti fasepembusukan (deterioration).

Stage of development at harvest

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RespirasiNon-klimakterik

RespirasiKlimakterik

Pendewasaan Pematangan Pelayuan

Laju

res

pir

asi

Perubahan selama proses pematangan: Warna Rasa Tekstur Terbentuknya vitamin Timbulnya aroma khas

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Buah digolongkan menjadi dua kelompok

Buah Klimakterik: pematangan terjadi setelah laju respirasimencapai puncaknya

Dipanen tua, lalu proses pematangan akan terjadi dengansendirinya

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Buah Non-klimakterik: laju respirasi terus menurun dan tidakmempunyai puncak

Dipanen setelah terjadi proses pematangan pada pohon

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Buah Klimakterik Buah Non Klimakterik

Apel

Markisa

Alpukat

Pepaya

Pisang

Nangka

Sirsak

Melon

Semangka Jambu biji

Tomat

Jeruk

Nanas

Anggur

Stroberi

Salak

Ketimun

Cabe

Bawang

PaprikaKakaoCherry

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Respiratory Substrat

Substrat gula/karbohidrat:

C6H12O6 + 6 O2 6 CO2 + 6 H2O + 675 kal

Substrat gula RQ = 6/6 = 1

Substrat asam organik RQ < 1

Berapa nilai RQ apabila substratnya Lemak?

Protein?

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2

O Konsumsi

CO ProduksiRQ Quotient y Respirator

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Preharvest factor

Lokasi tumbuh Iklim Musim Teknik budidaya pemupukan

The respiration of apples grown under conditions

of low Calcium nutrition is considerably higher

than that of apples with adequate supply of that

element.

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2. Environmental factors

a. Temperature

b. Atmospheric composition

i. Oxygen concentration

ii. Carbon dioxide concentration

iii. Ethylene

c. Physical stress

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Increased temperatures cause an exponential rise in the

rate of respiration which is expressed by the Vant Hoff rule:

The velocity of a biological reaction increases 2 to 3

fold for every 10 oC rise in temperature.

The temperature coefficient for 10 oC interval is called the

Q10 can be calculated by measuring the rate of the reaction (eg. respiration) at two temperatures:

0 10 oC Q10 = 2.5 - 3 10 20 oC Q10 = 2 2.520 30 oC Q10 = 2

Berapa kali laju respirasi buah-buahan/sayuran dari

suhu 0 oC ke suhu 30 oC ?

Pengaruh Suhu (Temperature effect)

12 TT

10

1

210

R

RQ

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Temperature Assumed Q10 Relative velocity of deterioration

Relative shelf life

0 1.0 100

10 3.0 3.0 33

20 2.5 7.5 13

30 2.0 15.0 7

40 1.5 22.0 4

Effect of temperature on rate of deterioration.

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Pengaruh Komposisi Gas (Atmospheric composition)

In tissues where metabolism is high, reduced oxygen concentration

increase the respiration rate, as measured by CO2 production.

The low ATP in the cell stimulates glycolysis (PFK is turned on) to

generate a modest amount of ATP and pyruvate NADH formed during the oxidation of triose phosphate must be reoxidized. This is

achieved by the reductive decarboxylation of pyruvate to ethanol.

C6H12O6 + 2 ADP + 2 Pi => 2C2H5OH + 2 CO2 + 2 ATP

To maintain the supply of ATP at the aerobic rate, 19 times as

many glucose molecules would be needed, and respiration would

increase 19 fold.

There would be substantial accumulation of ethanol, which is very toxic to plants.

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Pengukuran respirasi

jumlah substrat (gula) yang hilang

jumlah gas O2 yang digunakan

jumlah gas CO2 yang dikeluarkan

jumlah panas yang dihasilkan

jumlah energi (ATP) yang dihasilkan

TEKNIK PENGUKURAN RESPIRASI

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Because the rate of respiration is so tightly coupled to

the rate of cell metabolism, measurement of respiration

can afford an easy non-destructive means of monitoring

the metabolic and physiological state of the tissues.

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Menghitung substrat yang hilang

When hexose sugar is the substrate, 180 grams of sugar

are lost for each 264 grams CO2 produced by the

commodity.

Dloss = rate of dry weight loss (g/kg.jam)

%Dloss = persen dry weight loss per jam (%)

R = respiration rate (mg CO2/kg.jam)

264

180

1000

RDloss

10,000

0.68 x R%Dloss

Contoh:

Bawang pada suhu 30 oC respirasinya 35 mg CO2/kg.jam.

Berapa kehilangan berat kering setelah penyimpanan selama

satu bulan?

% 1.73 30 x 24 x 0.0024 bulan per lossesWeight

% 0.0024 000,10

0.68 x 35

10000

0.68 x R%Dloss

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Cepat persiapannya

Sederhana

Relatif cepat

Tidak dapat diterapkan dalam CAS/MAP

Tidak dapat digunakan untuk periode

penyimpanan lama

Ketelitian data riskan terhadap

kebocoran

Channel tube

Gas sampling port

CO2O2

Gas feeding

Produce

Glass jar 4.3 L

W

V

t

xR

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Closed System:

R : respirasi (ml/kg.jam)

X : konsentrasi O2 atau CO2 (desimal)

t : waktu (jam)

V : volume bebas (ml)

W: berat sampel (kg)

Mengukur Respirasi

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Open System:

Rumit persiapannya

Memerlukan unit pencampur gas

Boros dalam pemakaian gas

Untuk periode penyimpanan lama

Sangat diperlukan dalam perancangan CAS/MAP

W

QyGxR 111

W

GxQyR 222

3

3

x

QyG

Kesetimbangn O2

Kesetimbangan CO2

Kesetimbangan N2

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CO2O2

Produk Glass jar 4.3 L

Gas inlet

O2 : Y 1

CO2 : Y2

N2 : Y 3

Gas outlet

O2 : X 1

CO2 : X2

N2 : X 3

Flow in: Q Flow out: G

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UNIT PENCAMPUR GAS

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Komponen pengatur aliran gas

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Respiration jar

GC Integrator

Gas

sampling port

Plastic pipe

Mass flow meter

Air compressor

o Air humidifier

Incubator Toggle valve

Needle valve

Schematic diagram of respiration rate measurement system.

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Analisis Komposisi Gas Titrasi Metode Orsat Oxygen analyzer Infrared analyzer Kromatografi gas

Dr. Rokhani - TMB IPB

Dr. Rokhani - TMB IPB 36

KROMATOGRAFI GAS

Kromatografi cara pemisahan campuran yang didasarkan atas perbedaan distribusi dari komponen suatu campuran. Pemisahan

tersebut didasarkan pada dua fasa larutan, yaitu fase diam

(stationary) dan fase bergerak (mobile).

Keguanaan kromatografi gas (GC): Pengujian kemurnian zat tertentu Memisahkan komponen dari campuran Mengidentifikasi suatu senyawa

Kromatografi gas terdiri gas pembawa (carrier gas), ruang suntik sampel (injection port), kolom, oven, detektor,pencatat (recorder), dan panel kontrol.

Dr. Rokhani - TMB IPB 37

Flame Ionization Detector (FID)

Thermal Conductivity Detector (TCD)

Electron Capture Detector (ECD)

Flame Photometric Detector (FPD)

Thermionic Spesific Detector N, P spesific (TSD)

Photo Ionization Detector (PID)

Detektor kromatografi

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Pengukuran Respirasi Detektor: TCD Carrier gas: Helium Kolom: CTR I

WG-100

Dr. Rokhani - TMB IPB

Pengukuran Etilen Detektor: FID Carrier gas: Helium Gas pembakar H2, Udara Kolom: HayeSep T

Kolom tempat terjadinya proses pemisahan karena di

dalamnya terdapat fase diam.

Jenis kolom:

- packed column

- capillary column

Kolom kromatografi

Dr. Rokhani - TMB IPB 39

Dr. Rokhani - TMB IPB 40

Dr. Rokhani - TMB IPB 41

Kromatografi Gas (GC)

Days Hours CO2 (%) O2 (%)

1 8.00 2.3 19.7

10.00 5.3 16.6

2 8.00 2.2 19.6

10.00 4.2 17.3

3 8.00 2.0 19.8

10.00 3.5 18.1

4 8.00 2.1 19.9

10.00 3.3 18.5

5 8.00 2.3 20.0

10.00 4.6 17.4

6 8.00 2.3 20.1

10.00 3.6 18.5

7 8.00 2.3 19.7

10.00 3.1 18.6

8 8.00 2.3 19.7

10.00 2.9 18.8

Sampel : Mangga

Berat : 1.28. kg

Densitas : 1024 kg/m3

Volume stoples : 4300 ml

1. Hitung laju respirasi buah:

Laju produksi CO2Laju konsumsi O2

2. Tentukan nilai RQ

3. Gambarkan grafik laju

respirasi selama

penyimpanan dan jelaskan

pola respirasinya.

TUGAS

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