EVALUATION OF THE EFFECTS OF SELECTED POST-HARVEST PRACTICES AND TECHNOLOGY IN THE PRESERVATION OF STRAWBERRY FRUITS
ABSTRACT
This research evaluated the effects of selected post-harvest practices and technology on the preservation of hydroponic strawberries (Fragaria vesca L.). Strawberries were treated with chitosan coatings and calcium gluconate and stored at a cold temperature. Several quality attributes, including fungal decay, weight loss, surface color, firmness, total soluble solids, pH, and their correlations, were analyzed over a 10-day storage period. The results revealed that chitosan coatings effectively delayed fungal decay, reduced weight loss, and maintained firmness, contributing to an extended shelf life. The correlation analysis demonstrated strong associations between color and physico-chemical parameters. Coating optimization and further exploration of synergistic effects are recommended. Preserving the visual appeal of strawberries is essential, and consumer awareness can support sustainable post-harvest practices. Industry adoption of effective techniques is encouraged. Continuous research and innovation can lead to efficient and sustainable preservation methods, benefiting both producers and consumers.
CHAPTER ONE
GENERAL INTRODUCTION
- Background of the Study
The significance of agriculture in Nigeria cannot be overstated. Productive agriculture plays a pivotal role in providing high-quality food for domestic consumption, serving as a source of raw materials for agro-allied industries, generating employment opportunities that yield income, and fostering the growth of other industrial, commercial, and service sectors, while also contributing to foreign exchange earnings (Yusuf, 2015). The agricultural sector’s contribution to Nigeria’s Gross Domestic Product (GDP) has undergone notable changes. Crop production, which once accounted for approximately 85% of the total GDP in the early 1960s, steadily decreased to 47% in the late 1960s, further declining to 35% in 2002-2004, and reaching a low point of 21.2% in 2017 (World Bank, 2017). Despite this decline, agriculture remains a lifeline for the majority of the rural population, supplying raw materials to the industrial sector, and contributing to foreign exchange earnings through exports (Umaru, 2015). However, Nigeria’s agricultural production has struggled to meet the escalating food demands of its rapidly growing population (Gyimah-Brempong et al., 2016). Remarkably, Nigeria possesses abundant natural resources, including flowing rivers, extensive forested areas, and fertile arable land, totaling approximately 98.3 million hectares across various regions for crop cultivation (Oladimeji and Abdulsalam, 2014; Yusuf, 2015).
Strawberries are cultivated not only in many countries around the world but also in Nigeria. Strawberries, specifically Fragaria chiloensis, are a significant small fruit among the berry family, and they flourish in Plateau State, Nigeria. Various strawberry species can be found growing in the wild worldwide (Afridi, Ishaq, and Ahmad, 2009). Nutritionally, strawberries outshine citrus fruits, guava, and apples in terms of their higher protein, mineral, and vitamin content, as well as their increased digestible starch content. The nutritional profile of strawberries includes 100g of vitamin C, 89g of water in the edible portion, 0.07g of protein, 0.5g of fats, 8.4g of carbohydrates, and 59g of ascorbic acid (Afridi et al., 2009). In 2016, global strawberry production reached 4,895,459 metric tonnes (MT), with the United States being the largest producer, contributing 1,452,000 metric tonnes annually, representing 26% of the world’s total strawberry production. In contrast, Nigeria’s average production figure was 21,780 MT, accounting for approximately 0.45% of the world’s total strawberry output (Food and Agricultural Organization, 2017).
In Nigeria, strawberries are grown in limited quantities, primarily in the highland regions with temperate climates such as the Jos and Mambilla Plateau (Ogundele et al., 2018). However, due to the perishable nature of strawberries and the lack of proper post-harvest practices, significant post-harvest losses occur, leading to reduced profitability for farmers and limited availability of fresh strawberries for consumers (Ekwealor et al., 2020).
Post-harvest practices encompass a range of activities, including handling, sorting, grading, cleaning, packaging, and storage. Proper handling techniques such as gentle harvesting, avoiding bruising or damage, and rapid cooling are essential to minimize post-harvest losses (Siyam, 2019). Sorting and grading help to remove damaged or diseased fruits, ensuring only high-quality strawberries are selected for further processing or market distribution (Deb et al., 2020).
Cleaning strawberries using appropriate methods, such as washing with clean water or sanitizing agents, helps to remove dirt, microorganisms, and pesticide residues, thereby maintaining food safety and quality (Ogundele et al., 2018). Packaging plays a crucial role in protecting strawberries during transport and storage, preventing physical damage, and reducing exposure to humidity and oxygen (Ekwealor et al., 2020).
Alongside post-harvest practices, the use of post-harvest technologies has gained significance in strawberry preservation. Cooling systems, such as refrigeration or hydrocooling, are commonly employed to rapidly lower the temperature of harvested strawberries, which helps to slow down the ripening process and extend their shelf life (Siyam, 2019). Controlled atmosphere storage, involving the regulation of oxygen and carbon dioxide levels, can also be utilized to maintain strawberry freshness and delay senescence (Deb et al., 2020).
Modified atmosphere packaging (MAP) is another technology used for strawberry preservation, where the composition of gases within the package is modified to slow down respiration and microbial growth, thereby extending the shelf life of strawberries (Ogundele et al., 2018). Furthermore, post-harvest treatments, such as the application of fungicides or antimicrobial agents, can effectively reduce post-harvest losses by inhibiting the growth of fungi and bacteria that cause decay (Ekwealor et al., 2020).
To overcome the challenges associated with post-harvest losses of strawberries in Nigeria, it is crucial to adopt and implement appropriate post-harvest practices and technologies. By implementing proper handling, sorting, cleaning, packaging, and storage techniques, combined with the use of cooling systems, controlled atmosphere storage, modified atmosphere packaging, and post-harvest treatments, the shelf life of strawberries can be extended, reducing losses and increasing profitability for farmers (Siyam, 2019; Deb et al., 2020; Ogundele et al., 2018; Ekwealor et al., 2020).
1.2 Problem Statement
In today’s fruit market, ensuring the quality of fruits, including their nutritional content, microbial safety, and specific characteristics during storage, is imperative. Strawberries are among the most beloved fruits due to their appealing color and delicious taste, and they are also rich in valuable bioactive compounds (Dalmadi et al., 2007). However, strawberries are prone to rapid deterioration post-harvest, exhibiting symptoms such as desiccation, bruising, and fungal rots (Hernandez-Munoz et al., 2008). Fungal decay, in particular, is a common issue during postharvest storage, resulting in significant economic losses in the market (Hernandez-Munoz et al., 2008). The preservation of strawberries in Nigeria faces several challenges. The lack of appropriate post-harvest practices and technologies contributes to post-harvest losses, resulting in reduced economic returns for farmers and limited access to fresh strawberries for consumers. Furthermore, the absence of comprehensive research and evaluation of the effects of selected post-harvest practices and technologies specific to the Nigerian context hinders the development of effective preservation strategies for strawberries.
To meet the market’s demands, various technologies have been employed to extend the postharvest life of fruits. These techniques encompass chemical treatments (Nguyen et al., 2020a; Baranyai et al., 2020), edible coatings (Hazarika et al., 2019), radiation treatments (Jesus Filho et al., 2018), modified atmosphere packaging (Rux et al., 2016), ethylene absorbers (Nguyen et al., 2018), and moisture absorbers (Nguyen et al., 2020b).
1.3 Research Questions
The following research questions were formulated to guide the study:
- What are the prevailing post-harvest handling practices employed by strawberry farmers in Nigeria?
- What are the major factors that contribute to post-harvest losses in strawberry production in Nigeria?
- How effective are the selected post-harvest technologies in reducing post-harvest losses and extending the shelf life of strawberries in Nigeria?
- What is the impact of the selected post-harvest practices and technologies on the quality attributes (appearance, texture, taste, and nutritional content) of strawberries in Nigeria?
1.4 Research Objectives
The general objective of this research is to evaluate the effects of selected post-harvest practices and technologies on the preservation of strawberry fruits in Nigeria. Specifically, the study aims to:
- Assess the current post-harvest handling practices of strawberries in Nigeria.
- Identify the major factors contributing to post-harvest losses in strawberry production.
- Investigate the potential of selected post-harvest technologies in reducing post-harvest losses and prolonging the shelf life of strawberries.
- Evaluate the impact of selected post-harvest practices and technologies on the quality attributes of strawberries, including appearance, texture, taste, and nutritional content.
- Provide recommendations for improving post-harvest practices and technologies for the preservation of strawberries in Nigeria.
1.5 Significance of the Study
The findings of this research will contribute to the body of knowledge on post-harvest preservation of strawberries, particularly in the Nigerian context. The study will provide valuable insights into the current post-harvest handling practices and identify areas for improvement. The evaluation of selected post-harvest technologies will help farmers and stakeholders make informed decisions regarding the adoption of appropriate preservation methods. Furthermore, the study’s recommendations will serve as a guide for policymakers and researchers to develop strategies to reduce post-harvest losses, increase profitability, and enhance the availability of fresh strawberries in Nigeria.
1.6 Scope of the Study
This research will focus on evaluating the effects of selected post-harvest practices and technologies on the preservation of strawberry fruits in Nigeria. The study will cover the major strawberry-producing regions in the country, with a particular emphasis on the highland regions such as Jos and Mambilla Plateau. The research will involve data collection from strawberry farmers, post-harvest handlers, and relevant stakeholders. Laboratory experiments will be conducted to assess the impact of selected post-harvest technologies on the quality attributes of strawberries. However, this study will not include an in-depth analysis of the agronomic practices involved in strawberry production.
1.7 Definition of Terms
Before delving into the evaluation of the effects of selected post-harvest practices and technologies on the preservation of strawberry fruits in Nigeria, it is important to define key terms used throughout this research. The following section provides definitions of terms to ensure clarity and understanding of the concepts discussed.
- Post-harvest practices: Refers to the various activities carried out after the harvest of agricultural produce, including handling, sorting, grading, cleaning, packaging, and storage, to maintain the quality and extend the shelf life of the harvested crops.
- Post-harvest technologies: Encompasses the tools, equipment, and techniques used to enhance the preservation of agricultural produce after harvest. These technologies may include cooling systems, controlled atmosphere storage, modified atmosphere packaging, post-harvest treatments (e.g., fungicides, antimicrobial agents), and other innovative approaches aimed at reducing post-harvest losses and maintaining product quality.
- Preservation: In the context of this research, preservation refers to the application of various post-harvest practices and technologies to delay or prevent the deterioration of strawberry fruits, thereby maintaining their sensory attributes, nutritional value, and overall marketability for an extended period.
- Strawberry fruits: Refers to the edible, fleshy, and typically red-colored fruits of the strawberry plant (genus Fragaria). These fruits are highly perishable and are known for their characteristic aroma, sweet taste, and vibrant color. In the context of this research, strawberry fruits specifically pertain to those grown in Nigeria.
- Perishable: Describes the property of being susceptible to spoilage or decay, usually due to biological, chemical, or physical factors. Perishable fruits, such as strawberries, have a limited shelf life and require specific preservation techniques to maintain their quality.
- Shelf life: Refers to the period during which a product remains in good condition and retains its quality attributes, such as taste, texture, color, and nutritional value, under specified storage conditions. For strawberries, shelf life is the duration they can be stored without significant deterioration.
- Post-harvest losses: Represent the reduction in quantity and quality of agricultural produce that occurs between harvest and consumption. Post-harvest losses can result from factors such as improper handling, inadequate storage facilities, pest and disease infestation, and decay, leading to decreased market value and economic losses.
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