Post-Harvest Methodology and Technology for Horticultural Products in Agricultural Commercial Areas of Pakistan

Several factors Abstract | Electronic nose is an instrument, which comprises an array of electronic chemical sensors with partial specificity and an appropriate pattern-recognition system, capable of recognizing simple or complex odors. In the food industry, electronic nose is popularly used to detect smells and flavors of a wide range of food items. Latest steps are required for postharvest management through which the economy of horticultural products around the globe is almost at minimal losses. This review is highlighting the basic but truly important postharvest advancements to retain and maintain quality and quantity of vegetables and fruits. Significant outcomes are to be ensured in pre-harvest and postharvest handling and controlling the postharvest decay losses with these advanced techniques. Keeping an eye on good agricultural practices (GAP) standards, new advanced approaches should be reflected as gear of a combined decay control strategy. Postharvest decay is totally dependent upon harvest and handling practices. Environmental conditions mainly affect the fruit infection and source of contamination under subtropical climate while in tropical climates contamination of horticultural products affecting postharvest decay. Packaging of products in the fields may reduce the production costs but it heavily increased the postharvest decay. Mechanical damage impact can be identified the post-harvest decay by developing regression models. Additionally, new packaging materials have been introduced to avoid mechanical injuries and decline the chances of contamination, bruises and decays. Postharvest treatments includes biological agents, fungicides, herbal and natural products, edible coatings and heat treatments can be efficaciously applied in a vast and specific commodity range to prevent great losses.

like market availability, transportation facilities, food preservation techniques, harvesting and handling methods play an important role in post-harvest loses of horticultural goods. By taking advantage from the latest techniques and approaches, the developed states have reduced the losses in postharvest up to some mark but un-availability of mechanized methods and lack of awareness the developing countries are facing an immense challenge (Hodges et al., 2011). Weight and volume deterioration are considered under quantitative measurements while nutrient, color, aroma defined as the qualitative losses (Buzby and Hyman, 2012).
Because of both pre-post factors, decays may occur in products and the cause of pre harvest concealed contamination or infection during harvest. These latent infections further develop into symptomatic disease during storage, transportation and marketing of mostly fleshy horticultural products. The shelf and table life of vegetables and fruits partly depends upon pre-harvest managements and partly on postharvest handling. Efficient and sensible handling methods should be considered which are low in cost but high in profit afterwards when they prevent postharvest decay. It is an unelectable issue for the life of commodity and simultaneously maintains the nutritional value of the products (Michailides and Manganaris, 2009).
Over the last two decades, postharvest technology has evolved, there's insufficient importance on preharvest factors and its influence on postharvest decay. During or before post harvesting, initial steps are taken to avoid decay issues. Removal of propagules, which infects the crop in the field are the cause of latent inborn infection which plays an important fact in postharvest management. Significance of these processes, majority of agricultural industries that are dealt with horticultural products and byproducts have established a guide line known as good agricultural practices (GAP) These GAP should be started as soon crops are on bloom till harvest.

Objectives
• To minimize horticultural products losses during harvesting to costumer consumption. • To maintain products quality through sustaining qualitative determinations i.e. Exterior, texture, aroma and nutritive value.

Materials and Methods
Following are the contextual framework based on three primary basic methodologies i.e. qualitative, quantitative and mixed methods based on studies and surveys.

Edible coatings and natural products
In highly perishable fruit products, edible coatings are innovative and alternative means in postharvest chemical treatment (Valverde et al., 2005;Martinez-Romero et al., 2006). Their rate of succession is high giving a promising outcome in extending shelf life. During processing, these edible coatings act as a barrier during packaging, processing and in storage which ultimately enhance the quality and slow down the deterioration process. They are safe in use because they are made-up of natural biocides (antimicrobial compounds) (Petersen et al., 1999). Zein, alginate, starch, lipids, cellulose, milk proteins and wax are mainly used as edible coating on products (Cha and Chinnan, 2004). At commercial level, characteristics such as barrier properties, adhesion, low in cost and simple for production (Diab et al., 2001). In means of preservation, aloe vera gel has been used for quality maintenance and to avoid fungal activity or other pathogens A. alternate, P. digitatum, P. expansum and B. cinerea (Saks and Barkai, 1995) and can be extended to other commodities (Valverde et al., 2005).

Fungicides treatment
Because of high efficacy, many new fungicides replaced previously materials in managing the diseases of pre-harvest and postharvest of stoned fruit. Boscalid, cyprodinil, fenhexamid, pyrimethanil and pyraclostrobin have been very effective against brown rot fungi which is the main cause of fruit decay (Adaskaveg et al., 2005).

Inorganic compounds application
Microbial antagonists having potential when applied after harvesting than in the field. But these postharvest bio agents cannot control latent infections (Ippolito and Nigro, 2000). The influence of antagonistic yeast (Pichia membranaefaciens) on improving oxidative stress caused by (P. expansum) in cherries at maturity stage revealed no decay in yeast treated fruits up to 5 days after inoculation (Xu and Tia, 2008). The authors emphasized the antioxidant defense as an essential mechanism of antagonistic yeast in justifying pathogen induced oxidative stress to post-harvest produces and controlling post-harvest diseases.

Biological agents
Bio products i.e. nonpathogenic Pseudomonas strains ESC 10 , ESC 11 gave adaptable results and other products like ionized copper, calcium chloride, hydrogen dioxide and potassium carbide were ineffectual in managing soft rot (Edmunds and Holmes, 2009). Other ingredients like vinegar and acetic acid were very nominal in reducing the postharvest decay of pome and stone fruits (Sholberg and Gaunce, 1996).

Heat treatments
Over the last few years, horticultural crops were treated with heat effects after harvesting and their results are recently acknowledged (Mulas and Schirra, 2007).

Post-harvest technologies
Several preservation technologies like cold storage, modified-atmosphere packaging (MAP) and edible coating have been used for assured the vegetables and fruits; safe and hygiene.

Cooling
During storage and processing of vegetables and fruits, pre-cooling declines the temperature up to the level where it minimizes the chemical changes in the food product (Wijewardane, 2014). Researcher advised that maintaining temperature in storage rooms and cold rooms are suitable for products because it reduces the heat up to 75-90% but the hydrocooling cleaning system reduced the temperature five times faster than air cooling systems. Examples are of broccoli and sweet corn which were cooled with liquid icing. General estimation is found that half kg of ice reduced the temperature of 1.5 kg of the food product. For leafy vegetables, vacuum cooling was preferable because the vacuum removes the heat from the leaf tissues through vacuum pressure without drying them up (Bachmann and Earles, 2000).

Storage
Physiochemical quality of fruits at maturity level during storage minimized the total sugar level and decay process. Product maturity affects the quality parameters like total soluble solid (TSS) and total sugar content (TSC), weight and shelf life (Siddiqui et al., 2013a, b). It also observed in the mango which gradually increases with the increasing in time of storage (Roma et al., 2005). To prevent the mineral and vitamin losses, several vegetables and fruits require appropriate relative humidity (RH) and temperature (Abadias, 2008).

Packaging
By controlling the atmospheric oxygen and carbon dioxide within the packaging of products increased the shelf life of any product (Yumbya et al., 2014). Workneh et al. (2012) found in their observation that preserving the fresh vegetables and fruits up to long period without any quality deterioration, active packaging is most suitable.

Active packaging
Active packaging is the efficient barrier for moisture and gas emission during storage and marketing periods, which reduced the contamination chances and facilitated the handling processes (Ozdemir and Floros, 2004). Active packaging performance is the most suitable for numerous fruits and vegetables (Han and Floros, 2007). This type of active packaging system worked as reducer of oxygen which mainly decreases the respiration process of the packed commodities and carbon dioxide which increased the temperature of the product that retards the growth of micro-organisms. The moisture reduction the fastly controls the deterioration of the products. We can regulate time and temperature by indicators.

Perforated films
Perforated films kept the fruit and vegetable safe because of gaseous exchange through perforated layer as well as the entrance of gasses from polymeric film are balanced through gaseous movement rate (Fishman et al., 1996).

Modified atmospheric packaging
Modified atmospheric pressure (MAP) enhanced the table life of the product. Through this, the fruit life is increased from 3 to 4 weeks at 100 degrees which shows the best result than 1 week without modified packaging (Mohamed et al., 1996). This method decreases the ethylene production which reduces the enzymatic activity and improves the tomato quality with 3 percent oxygen and 20 percent carbon dioxide level (Sozzi et al., 1999). Ayhan et al. (2008) compared that carrots stored at 80 percent oxygen and 10 percent carbon dioxide extended the shelf life than at 5 percent oxygen. Through advance packaging technologies, different compositions can prevent the deterioration and increasing the shelf life of the horticultural products under cold storage (Argenta, 2004).

Future research
In post-harvest bio-control strategy and mode action of antagonistic yeast in postharvest diseases control play an important role by providing significant guidance for further research. In addition, biological agents with low risk fungicides should be carried out side by side to identify the best suitable for postharvest treatment with minimum environmental impact and taking in view the customer safety. Comparative studies are also required for the harvested products from conventional, integrated and organic production systems should also be carried out.

Future approach technologies
Keeping an eye on world population which rapidly increases expected in 2050 are 10.50 billion approximately which means the per capita demand of horticultural products has been increased. We can meet the difference by controlling the post-harvest losses. According to Kader and Rolle (2004) out of 100 the 95 percent research investment is directed to enhance the horticultural productivity in which only 5 remaining percent investment is involved in the postharvest losses reduction. Serious research and investment are required to minimize the losses especially in developing countries. Very limited resources were used for extension and research in postharvest processing of horticultural products during past 20 years (Kitinoja et al., 2011).

Conclusions and Recommendations
Numerous innovations and methods have developed which directly affects the quality of agricultural products and decrease the post-harvest decay. The ultimate goal is to provide safe and healthy product to the consumers with maximum organic residues and lower the chemical application and there is no doubt in that the handling of these agricultural products have direct effect on postharvest decay. No compromise on the health especially on life of products in storages to market till retailed stored periods. To overcome the scarcity of products, more emphasis is required around the globe. It will definitely increase the availability (per capita) by using modern technologies and just because of losses reduction without enforcing any other resources for enhancing the productivity and so production.

Novelty Statement
This work has been established on the basis of latest methodologies. With the up to date data, the said review paper is need of the day for commercial area of Pakistan where the negligence in packaging and processing of the agricultural goods to avoid and overcome the post-harvest losses. All the aspect and possibilities has been reviewed.

Author's Contribution
Asfand Raheel: Conceived the idea and write the paper according to idea. Syed Zulfiqar Ali: Prepared the review paper outlines and provided technical input each step. Muhammad Waris: Wrote the abstract and keywords. Muhammad Basharat: Collected the data and shared with the team for collaborative work. Basheer Ahmed: Formatted the paper according to the journal requirements. Muhammad Arshad Ullah: Technically improve the structure and back ground of the review paper. Syed Ishtiaq Hyder: Improve the English and grammar of the manuscript. Taqi Raza: Arranged the reference and citation if the paper according to journal requirement. Submitted final manuscript.