Quality and Preservation of Vegetables

Michael Eskin

• Éditeur: CRC Press
• Année: 2021
• ISBN:
  9781000446326
• Édition: 1
• Sujet: Sciences biologiques
• Sous-sujet: Horticulture

This comprehensive work discusses those factors which contribute to the overall quality of the major vegetables grown in North America for the fresh market as well as methods for storing and preserving these crops. The qualities which determine the suitability of a crop for processing is also discussed since the majority of vegetables, with the exception of lettuce and celery, are processed for the retail market. The selection of vegetables is based on their economic importance although several others are included for completion.

Chapter 1

POTATOES

D. K. Salunkhe, B. B. Desai and J. K. Chavan

TABLE OF CONTENTS

I.	Introduction
	A.	Historical Development
	B.	Botany and Taxonomy
	C.	Commercial Varieties
II.	Agronomic Characteristics of Potatoes
	A.	Yield
	B.	Shape and Size of Tubers
	C.	Flesh Color
	D.	Disease Resistance
	E.	Tuber Quality
III.	Quality and Storage of Raw Potatoes
	A.	External Quality
		1.	Size of Tubers
		2.	Shape of Tubers
		3.	Depth of Eyes and Skin Quality
		4.	Flesh and Skin Color
		5.	Greening: Development and Control
			a.	Acceptability
			b.	Association with Solanine
			c.	Control of Greening in Storage
				i.	Chemical Control of Greening
				ii.	Controlled Atmosphere (CA) and Subatmospheric (Hypobaric) Storage
				iii.	Irradiation
		6.	Sprouting: Development and Control
	B.	Internal Quality
		1.	Nutritional Quality
			a.	Carbohydrates and Energy
			b.	Proteins
			c.	Lipids
			d.	Minerals
			e.	Vitamins
		2.	Sensory Quality
		3.	Mechanical Damage and Physical Injury
			a.	External Damage
			b.	Internal Bruising (Blackspot)
IV.	Processing Quality of Potatoes
	A.	Texture
	B.	Specific Gravity and Tuber Composition
	C.	Starch Properties and Cellular Structure
		1.	Starch Properties
		2.	Cellular Structure
		3.	Structure and Composition of Cell Wall
	D.	Pigmentation
		1.	Enzymatic Browning
		2.	Nonenzymatic Browning
		3.	After-Cooking Blackening
V.	Processing of Potatoes
	A.	Control of Quality
	B.	Processed Potato Products
		1.	Potato Chips
		2.	French Fries
		3.	Other Frozen Products
		4.	Dehydrated Products
		5.	Canned Products
	C.	Effects of Storage on the Processing Quality of Potatoes
VI.	Quality Standardization of Raw and Processed Potatoes
	A.	Grading and Standardization
	B.	Federal Potato Grade Standards
	C.	Economics of Grading
	D.	Limits of Tolerances
	E.	Size of Grading
	F.	Specific Gravity Grading
	G.	Consumer Preferences
VII.	Conclusions
References

I. INTRODUCTION

The potato (Solanum tuberosum L.) with an annual production of nearly 300 million metric tons (t) is one of the major world food crops grown in a wide variety of soils and climates. Potato is superior to every other food crop in its ability to produce food per unit area per unit of time. The increasing awareness of the productive capability and food value of potato has placed this crop high in the order of importance, giving it a fourth rank after the world important staple food crops, viz., rice, wheat, and maize. Owing to their heavy yields, potatoes are relatively inexpensive and are the mainstay in the diets of people in many parts of the world. The U.S.S.R., Poland, U.S.A., China, India, France, Germany, and U.K. are the leading producers of potato. The total area, yield, production, and major producers of world potato are given in Table 1. Nearly one-half of the European potatoes are grown in Poland and Federal and Democratic Republics of Germany.¹

Table 1
THE TOTAL AREA, YIELD, PRODUCTION, AND MAJOR POTATO PRODUCING COUNTRIES OF THE WORLD

Particulars	1969—1971	1978	1979	1980
Area (1000 ha)	20086	18444	18380	18030
Yield (q/ha)	13.74	14.94	15.43	12.52
Production (1000 t)	275982	275511	283542	225718
Major Potato Producing Countries (Production × 1000 t)
U.S.S.R.	93739	86124	90956	66900
Poland	45013	46648	49572	26400
U.S.	14483	16616	15535	13653
China	11029	12529	12536	12537
Germany DR	10432	10777	12243	8568
India	4482	8135	10125	8306
France	8569	7467	7450	7485
Germany FR	15804	10510	8716	6694
U.K.	7359	7330	6485	6327

From FAO Production Yearbook, Vol. 34, Food and Agriculture Organization of the United Nations, Rome, 1981. With permission.

Table 2
TOTAL PRODUCTION OF DRY MATTER (DM) AND TOTAL PROTEIN, AND PRODUCTION OF DM, AND PROTEIN PER UNIT AREA OF MAJOR STAPLE FOOD CROPS

Crops	Total DM production (t × 10^7)	Total protein production (t × 10^6)	DM production (t/ha)	Protein production (t/ha)
Wheat	27.5	32.9	1.30	0.156
Rice	26.7	23.2	1.97	0.172
Maize	23.5	24.7	2.13	0.224
Barley	11.4	11.6	1.46	0.148
Sorghum/millets	8.2	7.4	0.73	0.066
Potato	6.6	6.0	2.93	0.266
Sweet potato/yam	3.9	2.9	3.82	0.280
Cassava	3.4	0.8	4.92	0.115
Soybean	4.2	16.7	2.62	1.043

From FAO Production Yearbook, Vol. 25, Food and Agriculture Organization of the United Nations, Rome, 1972. With permission.

Potatoes are an excellent source of carbohydrates and have significant contents of phosphorus, potassium, calcium, and vitamins, especially vitamin C. Their protein content of over 10% on a dry weight basis brings them relatively close to the 11% protein in wheat flour. Because of the high nutritive value and lysine content of potato protein, it is valuable supplement to cereal proteins.

On a world wide basis, the potato crop produces more dry matter (DM) and protein per unit area than the major cereal crops (Table 2), although about three times as much of the raw potatoes will have to be eaten to obtain an equivalent amount of energy to that of cereals. Potatoes thus serve as a significant source of proteins (10 to 15% of total protein requirements), a major source of vitamin C, and an important source of energy for industrial communities of the developed countries. In addition to ascorbic acid, potatoes also provide minerals, principally iron and vitamins such as thiamin, nicotinic acid, riboflavin, and vitamin A (beta-carotene). Various aspects of quality and preservation of raw and processed potato products are discussed in this Chapter.

A. Historical Deve...