How to Test Pre-harvest Quality in Fresh Produce

• All preharvest growing conditions and management practices affect yield and quality.
• Generalizations are challenging, as the same factor can have varying effects on different quality parameters of a single fruit.
• Recommendations for shared best practices to optimize yield and quality are given.

A significant percentage of food loss is attributed to decreased yield and quality due to preharvest factors in the fields and postharvest stages. However, the focus of cultivation activities has been only increasing yield. It is necessary to highlight the link between preharvest factors and postharvest loss in yield, quality, and consumer satisfaction.

Quality Attributes

Fresh produce quality includes appearance, organoleptic, and nutritional attributes, such as the following:

• Appearance attributes crucial for quality are size, shape, skin, and pulp color.
• Organoleptic properties include flavor, aroma, and texture. Flavor has two attributes: aroma and taste.
• Nutritional properties like levels of vitamins, phenols, carotenoids, antioxidants, minerals, etc., are also crucial as consumers become health conscious.

Optimum attribute levels characterize each fresh produce and its varieties. Any deviations lead to loss of quality and, in severe cases, of the product. Abiotic and biotic factors of all preharvest activities can affect yield and quality.

Table 1: “Fruit attributes of sun-exposed (exposed to the sun on the tree) and shade fruits (inside the canopy) in avocado,” Tyagi (2017).  DOI:10.9734/BJAST/2017/32909

Best Preharvest Practices to Improve Yield and Quality

Regardless of the species, region, soil type, or farming method, some common factors influence fresh produce yield and quality:

Field Preparation and Planting: Proper site allotment for different species and soil analysis to determine soil conditions to guide nutrition are necessary. Appropriate field preparation, crop density, and green mulching ensure optimum crop growth.

Selection of cultivars: Producers must choose cultivars and rootstock-scion combinations suited for their regions and marketing needs to get the best yield and quality harvest. Producers can control fruit quality, postharvest storage, and utilization potential through cultivar choice, as genetics also influences these attributes.

Planting time: Producers must sow seeds at the correct time in the season to synchronize with rainfall and allow time for crop development.

Plant Nutrition: Maintain optimum soil fertility to improve yield and quality parameters, including nutritional value. Nutrient deficiency can make fresh produce more susceptible to diseases during storage. For example:

• Calcium deficiency during tomato cultivation leads to blossom end rot in tomatoes.
• However, excessive nitrogen in tomatoes reduces total soluble solids and pH.

Provide optimum irrigation: Water content is crucial for seed germination and growth, which enhances yield and quality. However, over-irrigation increases disease risk, leading to postharvest decay and weaker green vegetables. Less water in tomatoes can reduce yield but increase total soluble solids.

Control diseases, pests, and weeds: Biotic factors in the field affect quality in various ways, even in the postharvest stages.

• Crop rotation and disease-resistant varieties can reduce disease incidence to avoid postharvest decay.
• Reduce pests by using integrated pest management practices to prevent blemishes on fresh produce.
• Weeds lower quality and yield by competing for resources and space and acting as disease vectors.

Agricultural practices: Management activities like mulching can reduce disease and water scarcity. Staking, pruning, and thinning of leaves increase light penetration, influencing fruit ripeness and quality development.

• Light helps color development, but tomatoes from shade have deeper red fruits.
• Sun exposure is good for ascorbic acid development.

So, management practices must be suited for the end use of the produce.

Maturity Stage: Even when all conditions are optimum, if the fresh produce is not harvested at the correct maturity, it can affect the quality and nutritional value of harvested produce, storability, and consumer satisfaction. Producers can use quality attributes as indicators of maturity or harvest index to check maturity and fix harvest time. Fruit quality improves with maturity but reduces storability, so maturity indices are carefully estimated. Popular harvest indices are skin color, dry matter, sweetness, and firmness.

Meters For Testing Pre-Harvest Quality

To monitor fruit quality development, it is better to use non-destructive devices to save crops. Felix Instruments Applied Food Science offers a near-infrared spectroscopy-based F-750 Produce Quality Meter and the F-751s quality meters for Avocado, Kiwifruit, Mango, and Melon. These devices accurately measure dry matter, total soluble solids (Brix), titrable acidity, and color in real time. Harvesting fresh produce at predetermined optimum maturity for high yield, good quality development, storability, and consumer satisfaction to cut food losses is possible.

Sources

PennState Extension. (2017, July 31). Keeping Produce Fresh: Best Practices for Producers. Retrieved from Keeping Produce Fresh: Best Practices for Producers (psu.edu)

Benedicta Adewoyin, O. (2023). Pre-Harvest and Postharvest Factors Affecting Quality and Shelf Life of Harvested Produce. IntechOpen. doi: 10.5772/intechopen.111649

Tyagi, Sachin. (2017). Pre-harvest Factors Influencing the Postharvest Quality of Fruits: A Review. Current Journal of Applied Science and Technology. 23. 1-12. 10.9734/BJAST/2017/32909.