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The design and structure of a warehouse should facilitate proper ventilation, temperature control, and protection from pests. This includes features like smooth floors, durable walls, and proper drainage systems to prevent water accumulation. The warehouse should also be insulated to protect stored goods from extreme temperatures and humidity fluctuations.
Regular maintenance is essential to keep the warehouse in good condition. This involves routine checks for structural integrity, such as inspecting for cracks, leaks, or signs of pest infestation. Equipment like ventilation fans, conveyors, and lighting should be regularly serviced to ensure optimal functioning.
Sanitation and hygiene are equally important in preventing contamination and pest issues. The warehouse should be thoroughly cleaned to remove any dust, dirt, or residues that could harbor pests or mold. All surfaces, including walls, floors, and storage bins, should be disinfected regularly. Proper waste disposal systems should be in place, and areas where food products are stored should be kept free from garbage or organic waste that could attract pests. Ensuring a clean and well-maintained warehouse helps preserve the quality and safety of stored goods.
SELECTION OF STORAGE TYPE
Some basic Guildelins or Principles are Given as Follows:
ROUND OR RECTANGULAR STORAGE
In terms of structural cost per tonne of storage, round storage buildings are generally more cost-effective than rectangular ones. The reasons for this are straightforward:

The quantity of space available for product storage is referred to as warehouse capacity. Understanding the distinction between theoretical working capacity and storage capacity can be aided by warehouse capacity. In warehouses and other storage facilities, space is perhaps the most valuable resource for online retailers. By making the most of their warehouse space, businesses can significantly increase the quantity of goods they can store there. Having more things in storage at once can save them money on transportation and other expenses.
It also makes it easier for the warehouse KPI staff to access the products, which helps them process orders faster and deliver the goods to customers sooner. Because space can be limited in a warehouse setting, warehouse managers and business owners should take the time to assess how much space they have and how well they’re using it.
STEP TO CALCULATE WAREHOUSE STORAGE CAPACITY
Understanding your warehouse’s current capacity is the first step in
determining how to increase it. This brief guide will show you how to calculate a
warehouse’s capacity in feet:
• Calculate the total square footage of your warehouse complex. Let’s assume that it is 10,000 square feet in this case.
• Determine the total amount of space devoted to non-storage purposes, such as offices, loading areas, restrooms, and break rooms. Assume for the moment that this is equivalent to 2,000 square feet.
• Subtract the total square feet of non-storage space from the total square feet of your warehouse to determine the usable space. The following is the equation:
USABLE SPACE-TOTAL SQUARE FEET – NON-STORAGE SPACE SQUARE FEET
Determine the total usable storage space by identifying the maximum stack height or clear height. This should account for the lowest-hanging overhead

Cleaning, drying, and aeration are essential processes in the management of stored agricultural products to maintain their quality and reduce the risk of spoilage. These practices are particularly important in preventing the growth of molds, the infestation of pests, and the deterioration of the product during storage.
Cleaning is the first step in the storage process. It involves removing any debris, dust, dirt, and residues from both the stored products and storage facilities. Proper cleaning eliminates potential sources of contamination, such as pests, molds, and bacteria, which can thrive in the presence of organic matter. It also ensures that the grain or other stored product is free from contaminants that could affect its quality and marketability.
Drying is equally crucial to prevent moisture-related issues. Excess moisture can lead to mold growth, fungal infections, and insect infestations. Drying reduces the moisture content of the grain or product to safe levels, typically below 14% for grains, which helps preserve their quality during storage.
The drying process can be carried out using natural sunlight or mechanical dryers, depending on the volume of the product and available resources. Properly dried products are less prone to spoilage and can be stored for longer periods. Aeration involves the circulation of air through stored products to maintain optimal temperature and humidity levels. By controlling the environment, aeration helps prevent the buildup of heat and moisture, both of which can lead to product deterioration.
It also reduces the risk of insect infestations by keeping the grain cool and dry. Aeration systems typically use fans or ventilation channels to ensure continuous airflow, especially in large-scale storage facilities. Together, these processes form a comprehensive approach to maintaining the quality and safety of stored agricultural products.

Warehousing is a critical national strategy for conserving food grains. The proper storage and maintenance of notified commodities, primarily food grains, alongside safeguarding them from adverse weather, rodents, and natural decay, are vital for fostering the growth and development of the agricultural sector.
Post-harvest losses contribute to approximately 10% of total food grains, primarily due to improper storage methods, insects, rodents, microorganisms, and birds. The Punjab State Warehousing Corporation (PSWC) takes on the responsibility of storing, handling, and warehousing notified commodities, including agricultural produce, industrial raw materials, finished goods, and various perishable and hygroscopic items. PSWC provides scientifically designed warehouses that protect both the quality and quantity of stored goods, aided by trained personnel.
At PSWC warehouses, stored products are safeguarded from rodents, pests, and moisture, ensuring their preservation. The provision of scientifically managed storage facilities for food grains, from procurement to distribution, is a vital function carried out by PSWC. PSWC has made significant strides in creating warehousing facilities throughout the state, constructing numerous warehouses in key rural and urban areas.
Rail-side warehousing facilities have also been established, offering costeffective and efficient storage solutions under a unified approach. Additionally, PSWC helps prevent distress sales, enabling producers to hold their products until favorable market conditions arise, thereby securing the best possible value for their goods.
Horizontal sheds are commonly used to offer low-cost, large-volume storage, and the Food Corporation of India (FCI) has also built very large sheds for storing grains and other products. These sheds typically feature steel or corrugated sheet

Agricultural professionals continuously confront challenges in preventing pest infestations and managing temperature and moisture levels to protect grains from decay. They recognize the critical importance of safeguarding these valuable resources and rely on quick, dependable solutions to tackle common grain storage issues. Let’s take a closer look at the challenges faced by growers, handlers, transporters, and processors in long-term grain storage, and the strategies they employ to overcome these obstacles.
ABIOTIC FACTORS
There are also abiotic factors, which are non-living elements, that influence the quality of stored grains. Factors such as air, humidity, and temperature play a significant role in grain storage. If these factors are imbalanced in terms of quantity or quality, they can have a detrimental effect on the stored grains.
SPACE CONSTRAINTS
As crop yields continue to rise, farmers face the challenge of finding enough storage space to accommodate the increased harvest. Often, last year’s grain still fills storage bins when the new crop arrives, prompting the agricultural industry to seek innovative storage solutions.
The most straightforward solution to a shortage of storage space is to build additional bins. However, this option is not always feasible for smaller farms or processing facilities with limited budgets. As a result, many choose to repurpose existing barns or store surplus grain outdoors in piles. Unfortunately, this outdoor storage method comes with its own set of challenges, including faster spoilage and pest issues. To counter these problems, some facilities use temporary storage options such as grain bagging systems or outdoor storage tents. Mechanical ventilation systems are also employed to ensure proper aeration, reducing the risk of spoilage before the grain is moved to its final destination.

Food is a vital requirement for all living beings, as it provides the essential nutrients necessary for growth, development, and recovery. Humans depend on both plants and animals for nourishment, which we acquire through agricultural practices and animal farming. With the increasing global demand for food, crop yields have risen, which has led to a greater reliance on warehouses for grain storage. However, merely increasing food production is insufficient to combat hunger and malnutrition, as food security also heavily depends on ensuring that food is accessible to everyone. Crops, however, are exposed to various threats, such as pests, weeds, and diseases, which can drastically reduce yields if not managed adequately.
A significant issue is storage losses, which are driven by both biological elements (such as fungi, insects, and rodents) and environmental factors (such as unsuitable storage conditions or extreme temperatures). These losses result in various negative consequences, including:
• Reduced food quality
• Lower seed germination rates
• Loss of weight in crops
• Discolored produce
These problems can impede the marketing of harvested crops, leading to unsold goods and considerable losses for farmers and distributors.
To reduce these losses, it’s crucial to adopt proper measures like efficient treatments and continuous monitoring of storage conditions. Grains should be stored in environments that prevent deterioration. This can be achieved by ensuring thorough cleaning before storage, drying grains thoroughly (both under the sun and in the shade), and taking steps to control pests, including fumigation.

1. MATURITY INDICES
Maturity indices (right time of harvesting) are quality factors that give clues as to when a product should be harvested to allow marketing flexibility and ensure the attainment of minimum acceptable quality to the user. It also refers to the set of criteria used to determine the stage of maturity for harvesting the horticultural crops. Commodities harvested either pre-mature or too late are more susceptible to postharvest physiological disorders, diseases and have poor shelf life than harvested at right stage of maturity. The pickers/ handlers are trained in methods of identifying produce that is ready for harvest. However, optimum harvesting stages depends upon type of produce and their final use. Horticultural crops may be harvested at two main maturity levels i.e., physiological maturity and commercial or horticultural maturity. Therefore, the proper stage/maturity indices for harvesting of all horticultural crops should be identified for their implementation during harvesting. Horticultural maturity in relation to developmental stages of the plants is depicted in Fig 3.1.
Maturity indices are different for different horticultural crops and are employed to:
1. Ensure sensory quality (flavour, colour, aroma, and texture) and nutritional quality: Harvesting horticultural produce too early (under-developed or immature produce) will result

I. INTRODUCTION
The fruits and vegetables we eat and flowers and ornamentals we enjoy are biological entities. They breath, produce heat, perspire, are easily damaged, get diseases and finally die. These carry on processes characteristics of all living things before or after harvest to perform the metabolic activities:
1. to maintain cellular organization
2. to transport metabolites around the tissue and
3. to maintain membrane permeability.
The job of postharvest technologist is to understand life in fruits, vegetables and flowers and prolong their life as much as possible. The post harvest life of produce depends on the rate at which they use up their stored food reserves and their rate of water loss. The sugar and starches (carbohydrate derivatives) are stored in various parts of plants through a process known as photosynthesis occurring in growing plants and are used later to provide energy for further growth, development and to prolong post-harvest life. The process of photosynthesis in growing plants and respiration in harvested produce can be seen in Fig. 2.1. The released energy through process known as respiration occurs in plants before and after harvest. Thus, principal normal physiological processes leading to aging are respiration and transpiration.

I. INTRODUCTION
Horticultural crops include fruits, vegetables, flowers, plantation crops, spices, and medicinal and aromatic plants have emerged as a major economic activity in India. It contributes 30% GDP from 11.73 % of its arable land area. Horticulture crops cover over 23.4 million hectares of area, which is approximately 12.7% of the total gross cropped area of the country and contributes 18-20% of the gross value of India’s agricultural output (NHB, 2013). India is the world’s second largest fruit and vegetable producing country accounting for 77.7 million metric tonnes of fruit and 159.5m M tonnes of vegetables (NHB, 2013). Besides, about 5.66 million tonnes of loose flowers, spices, mushroom and aromatic plants are also produced. The country produces 41% of world mangoes, 23% banana, 24% cashew nut, 36% green peas, 10% onion and 30% cauliflower and accounts for 12% of world fruit and 13.25% of vegetable production (NHB, 2013). Owing to wide diversity of agro climatic conditions, almost all types of temperate (apple, peach, plum, apricot, cherries and nuts), subtropical (mango, guava, papaya, etc), tropical (banana, pineapple etc), arid fruit (ber and aonla), plantation crops (coconut, cashewnut and arecanut) and diverse variety of vegetables are grown in India. The export of fresh fruit and vegetables from India in 2006-07 was estimated at 9.84 Lakh tonnes valued at Rs 2411.70 crores. Mango, grapes, apple, onion, potato, green vegetables like okra, bitter gourd and green chillies were the major items of export. Similarly, India exported 5.97 Lakh tonnes of processed foods comprising of mango pulp, juices, concentrates, dried and processed vegetables, pickle and chutney, alcoholic and non-alcoholic beverages worth Rs 2818.1 crores (APEDA, 2012) (Table 1 to 3).

Carbohydrates (glucose) are the primary energy source for a body; when digested, glucose is the end product in human beings and simple stomach animals, but it yields volatile fatty acids in ruminants. Precise regulation of levels of blood sugars/glucose in the body is the net result of various processes like digestion, absorption, and metabolism operating under the interaction of various a) enzymes and b) hormones secreted by the different organs of the body. An abnormal secretion of any of the enzymes or hormones associated with the metabolism of carbohydrates disrupts the precise regulation of blood sugar, leading to various disorders.
14.1 Enzyme Deficiency and Disorders in Carbohydrate Metabolism
Usually, various enzymes are involved in the breakdown of carbohydrates, and if their secretion is insufficient, missing, or does not work correctly, it leads to different disorders.
I. Glycogen storage diseases (GSDs, glycogenosis, and dextrinosis)
Glucose is needed by the cells for the generation of energy and other cellular activities. If glucose happens to be in excess, it is stored as glycogen, mainly in the liver and muscles, for future needs. The stored glycogen can be converted back to glucose when the need arises. Many enzymes are related to this interconversion of glucose and glycogen. Deficiencies of one or more enzymes may lead to abnormal glycogen metabolism, leading to glycogen accumulation of normal or abnormal chemical structure in tissue, collectively called glycogen storage diseases (GSDs). Roman numerals identify different types of glycogen storage conditions. They are also classified under various categories like inherited metabolic diseases, autosomal recessive type, and X-linked type (VIII/IX type).

The number of hormones secreted by the body exhibits control over the physiological regulation of glucose sugar level (homeostasis) in the manner needed by the body. Depending upon the situation, hormones may increase or decrease the level of glucose sugar present in the blood or tissues. The glucose is oxidized to yield energy, carbon dioxide, and water.
Glucose, more than the body’s needs, is stored or converted mainly to glycogen and, to some extent, protein and fat. If glucose is less than the need of the body, its denovo synthesis takes place from amino acids or fatty acids, or is formed from the breakdown of stored glycogen. Various hormones are secreted by multiple endocrine glands to control the blood glucose level. If it fails, it leads to hypoglycemia or hyperglycemia conditions. Gluconeogenesis is not developed at birth in the case of a baby pig. Therefore, hypoglycemia in baby pigs is observed within 2 days of age if starved, leading to hypoglycemia, weakness, confusion, and death.
15.1 The Hormones Involved in Homeostatic Regulation of Blood
Glucose Level
The hormones influencing carbohydrate metabolism are explained below:

Glycogen breakdown is known as glycogenolysis. This breakdown occurs in the cytoplasm of cells of the organs, wherein glycogen is stored. The end product of glycolysis is glucose in the liver, which is glucose-1-phosphate in skeletal muscles.
Glycogen is a polysaccharide synthesized from glucose monomers. Glycogen is stored in the cell instead of glucose because glucose requires more water, whereas glycogen can be stored with much less water. Most of the stored glycogen is in the liver (5% of body weight) and muscle (1 to 2 % of body weight). Muscle and liver glycogen undergo glycolysis for different purposes. Muscle glycogen provides energy for muscular activity, whereas liver glycogen helps to maintain the blood glucose level.
Glycogen contains many glucose residues (up to 120,000) linked by alpha 1-4 glycosidic bonds, forming a straight chain. Glycogen has branches at alpha 1-6 glycosidic bonds at every ten glucose residues. At the reducing end, the carbon one of glucose is free, whereas it is not accessible in the case of non-reducing ends.

Glycogenesis helps to maintain blood glucose, as it is a primary source of energy for every cell. An inadequate supply of glucose to the body may lead to the failure of the vital organs. Glucose, when in excess, is synthesized into glycogen and stored (glycogenesis), mainly in the liver and muscles (including the uterus). It is also found in other tissues, such as the kidney, brain, heart, and adipose tissues. The stored liver glycogen is broken down (glycogenolysis) into blood glucose when needed. Still, the glycogen stored in muscle is broken down to glucose 1-phosphate and converted to blood glucose later. Either the synthesis or breakdown pathway is primarily active at a time in tissues. Glycogen synthesis and its breakdown are not reversible processes.
The percentage of glycogen stored in skeletal muscles is less ( 1% to 2%) than in the liver (10%). Still, the total quantity of glycogen is greater in muscles due to their greater mass than an animal’s total liver mass. Muscle mass, on average, ranges from 40 to 45 % of body weight for the most mature mammals.
Glycogen synthesis (glycogenesis) is an anabolic process forming a branched homopolysaccharide made of several chains of alpha D-glucose units linked by α-1,4 glycosidic bonds in a linear chain and nearly every ten glucose residues; the chain branches off via α-1,6 glycosidic linkages. The α-glycosidic bonds give rise to a helical polymer structure. The number of glucose units in a single glycogen molecule varies (1,700 to -600,000 units). The glycogen granules are formed on the glycogenin protein in the center, so it acts as a primer, and their number determines the total number of glycogen particles.

Plants, with the help of photosynthesis, convert simple molecules (like carbon dioxide and water) into more complex molecules (anabolism) through various chemical reactions. Animals synthesize more complex molecules (anabolism) from monomer units through multiple chemical reactions. Anabolism refers to a biosynthesis process involving the sequences of biochemical reactions by which complex molecules are formed in living cells from available monomer units. Anabolic processes include the biosynthesis of complex biomolecules like carbohydrates, proteins, and lipids. The anabolic processes require energy from high-energy bond compounds like ATP.
The anabolic processes related to the biosynthesis of carbohydrates include
(1) Gluconeogenesis and
(2) Glycogenesis
11.1 Gluconeogenesis
Gluconeogenesis is the synthesis of new glucose molecules from noncarbohydrate molecules. The non-carbohydrate molecules that are used for gluconeogenesis are derived from glycolysis, lipolysis, and proteolysis. Examples are pyruvate, lactate, glycerol, and glucogenic amino acids. The liver and kidneys are the preferred organs for the gluconeogenesis process. It also occurs to some extent in the brain. Blood glucose levels are maintained at physiological concentrations through the process of gluconeogenesis in humans and ruminants. The blood glucose drops below normal levels during various conditions like fasting, starvation, pregnancy, lactation, fever, and low carbohydrate diets.

The uronic acid pathway is a minor and alternative pathway for glucose oxidation and for the production of uronic acid sugar. Uronic acids of sugars are formed when the terminal carbon’s (C6) hydroxyl group (CH2OH) of sugar gets oxidized to a carboxylic acid. Uronic acid names depend on the name of the parent sugars. Uronic acid of glucose is glucuronic acid, hexose uronic acids are hexuronic acids, and pentose uronic acids are named penturonic acids. The uronic acid pathway is located in the cytosol of the liver and adipose tissue.
The glucuronic acid should not be confused with gluconic acid (aldonic acid) and glucaric acid (aldaric acid or dicarboxylic acid). Gluconic acid (aldonic acid or “onic” acid) is obtained from D-glucose by oxidizing its aldehyde group at C1 to a carboxyl group. Glucaric acid (aldaric or dicarboxylic acid) is formed upon oxidation of both the terminal hydroxyl groups (C1 and C6) and the aldehyde. They have two carboxylic acid groups. This pathway yields pentoses & ascorbic acid or vitamin C (not in primates & guinea pigs) from glucose.

This alternative pathway for glucose oxidation has enzymes in the cytosol through which glucose is degraded to carbon dioxide. It is also called a shunt because carbon atoms from glucose 6-phosphate take a long route before they proceed down the EMP or glycolytic pathway. This pathway is anabolic in nature as it produces many intermediates. In this pathway, two NADPH are generated from one glucose 6-phosphate molecule. No ATP is generated or consumed.
Overall, this pathway needs three glucose-6-phosphate molecules to complete all the reactions. Therefore, one cycle run produces 2 mol of fructose-6- phosphate, 1 mol of glyceraldehyde-3-phosphate, and 3 mol of carbon dioxide from 3 mol of glucose-6-phosphate with the reduction of 6 mol of NADP+ to NADPH.
Overall reactions of the HMP pathway are as follows:
3 Glucose-6-P + 6 NADP+→ 3 ribulose-5-P + 3 CO2 + 6 NADPH
3 Ribulose-5-P → 2 xylulose-5-P + Ribose-5-P
2 Xylulose-5-P + Ribose-5-P → 2 fructose-6-P + Glyceraldehyde-3-P

The Hans Krebs cycle, known by different names like the citric acid or tricarboxylic acid cycle, was named after the scientist Hans Krebs. The citric acid cycle is named after the citrate product formed in the cycle. The name tricarboxylic acid is given as citrate itself, which is a tricarboxylic acid due to the presence of three carboxyl functional groups (-COOH).
The tricarboxylic acid (TCA) cycle occurs in aerobic conditions and within mitochondrial ETC, involving various sequential oxidoreductase reactions. The cycle requires Acetyl-CoA (C2 molecule) and oxaloacetate molecule (C4 molecule) to begin with the formation of a citrate molecule (C6 molecule). Acetyl-CoA is generated from the pyruvate (glycolysis), the fatty acids (lipolysis), or by oxidative deamination of specific amino acids. The complete oxidation of a glucose molecule results in the end products like energy (ATP), CO2 and H2O. A molecule of Acetyl-CoA has two carbons. It is formed from a three-carbon pyruvic acid molecule generated from the glycolysis of a sixcarbon glucose molecule. Acetyl-CoA is the substrate for this cycle and is an energy-rich molecule having a thioester bond between coenzyme A and acetic acid.
8.1 Formation of acetyl-CoA from Pyruvic Acid
Pyruvate is obtained by glycolysis or the oxidation of glucogenic amino acids. The pyruvic acid produced in the cytoplasm crosses the inner membrane of the mitochondrion to enter the mitochondrial matrix, where it undergoes oxidative decarboxylation, forming Acetyl-CoA. Acetyl-CoA carries (carrier molecule) the acetyl group to the citric acid cycle. It also links various metabolic products with the TCA cycle. Such products can be from the EMP cycle, beta-oxidation, and oxidative deamination of amino acids. Oxidative decarboxylation of pyruvic acid needs a complex enzyme system known as pyruvate dehydrogenase

Glycolysis involves a series of reactions to extract energy from glucose to
release two molecules with three carbons called pyruvate. The process is not
dependent on oxygen but can occur under aerobic and anaerobic conditions,
releasing different end products. Under aerobic conditions, the pyruvate formed
is then oxidized in the mitochondria to CO2 and H2O. The energy released in
glycolysis is in the form of ATP (High Energy Bond). All the reaction steps
occur in the cytoplasm, as it is the extramitochondrial pathway. In anaerobic
conditions and the absence of mitochondria (RBC), the end product of
glycolysis is lactic acid.
The net reaction of Glycolysis (anaerobic) may be summarized as under
Glucose + 2ADP + 2Pi → 2 Lactate + 2ATP
7.1 Steps in EMP Cycle or Glycolytic Pathway
Table 7.1: Steps and enzymes of glycolysis or EMP cycle.

6.1 Metabolism
Dietary components like carbohydrates, lipids, and proteins are continuously broken down and synthesized through various chemical reactions (exergonic or endergonic) that are concerned with energy. These processes not only break them down but also interconvert them for their synthesis. Dietary components, when utilized, are known as nutrients the body. The number of reactions occurring in living cells maintains the body cells and fluid’s homeostasis and dynamic status. To keep the dynamic state of a cell, many reactions are going on to synthesize or break down the different types and sizes of molecules. The total of these reactions is known as metabolism.
The metabolism may be anabolic or catabolic. Further, it may be aerobic or anaerobic, depending on oxygen availability. These four terms are explained below:
I. Aerobic and Anaerobic Metabolism
• Aerobic metabolism-- In aerobic metabolism, the carbohydrates (substrate) in the presence of oxygen are metabolized to release energy, carbon dioxide, and water. The released energy is converted to ATP by two processes in the mitochondria (the Krebs cycle and oxidative phosphorylation). In oxidation, the electrons released from a glucose molecule are transferred to reduced NAD+ and FAD. The oxygen (electron acceptor) is reduced to water. Water formation [from H2(g) and O2(g)] is an exothermic reaction. The energy released from the chemical bond of glucose is captured as ATP, and heat is released.

Polysaccharides comprise several monosaccharide units (more than ten) linked by glycosidic bonds; therefore, they are high molecular weight carbohydrates. They are also called polyanhydrides of simple sugars. The most common monosaccharide unit of polysaccharides is D-glucose. The polysaccharides may differ in their monosaccharide units, molecular weight, chain nature, glycosidic bond types (alpha, beta), and linkages (1-2, 1-3, 1-4, or 1-6). They are tasteless, colorless, amorphous powders that are a little water-soluble. Some may form colloidal solutions. The polysaccharides provide structural stability (structural polysaccharides) to cells, prevent cells and tissues from drying out due to their water-binding properties, and reserve food for the future. Reserved polymeric carbohydrates are osmotically less active and can be stored in large quantities within the cell.
The right and left end of polysaccharides, respectively, are called the reducing and non-reducing ends. Based on the functional aspects, they are grouped in two ways.
• The first way depends on its digestibility—1. Nutrient polysaccharides are (digestible) starch, dextrin, and glycogen, and 2. Structural polysaccharides are (indigestible), chitin and cellulose.
• The second way, depending upon the constituent monosaccharide units, they are 1. Homoglycans (same units), and 2. Heteroglycans (different units).