Introduction
Roughly 1/3rd (1.3 billion tonnes) of the food produced in the world for human consumption every year gets wasted. Out of the total produce, fruits and vegetables have the highest wastage rates of almost 40-50% (1)
In the post-harvest period, control of ethylene generation is of utmost importance to extend shelf & transit life of fresh produce.
Current Market Solutions to tackle Post-Harvest Losses are Cold chains, multi-commodity cold storages, Controlled Atmosphere Storages, Distributed Refrigerated architecture, Electronic controllers, Ripening chambers,
Gas scavengers, Ethylene adsorbers / scavengers oxidisers & Modified Atmosphere Packaging. But these technologies are expensive & require special expertise.
In continuation of our earlier work (2), in this paper, we are reporting 3 new approaches – 1) Conversion of ethylene-to-ethylene oxide which acts as a disinfectant and preserves biological damage to fruits and vegetables, 2) Partial adsorption of ethylene to reduce ethylene in the packaging environment and 3) To incorporate halogen generators in the packing film to convert the ethylene in corresponding ethylene di-halides which are good insecticides at very low concentration.
Materials and Methods
Materials:
The Bags used for this experiment were prepared in LDPE & NYLON. All were of same & were for every product testing, Control Bags of LDPE were used for comparison.
Table-1 gives details of the food products tested in Efficacy Testing.
Table-1: Food products tested in Efficacy Testing.
No. | Product | Food Products |
1. | Freshness Plus Bags | Pomegranate |
2. | Lifeguard Bags | Mangoes |
3. | Halogen- CL Bags | Banana |
4. | Halogen-BR Bags | Banana |
5. | Halogen-IO Bags | Banana |
- Quantitative Analysis –to check reduction in ethylene & carbon dioxide gas concentration in Bananas.
- Efficacy Testing – to study improvement in the shelf-life extension of fresh produce due to ethylene reduction.
- Quantitative Testing:
- Labeling of Test Samples (Table-2)
- Selection of Food Samples: Bananas were procured in semi-ripe form, no visual defects & with uniform maturity. Bananas were packed in perforated test films (0.5-0.7Kg per package) and stored at 20ºC.
- Ethylene Concentration: The reduction in ethylene concentration was measured over a period of 7 days.
- Carbon Dioxide Concentration: % CO2 content was measured in each test bag over a period of 7 days.
- Efficacy Testing:
- Selection of Food Samples: Fruits and vegetables were procured in semi-ripe stage, with no visual defects and of uniform maturity.
- Placement of Bags: 500 gms of each of the respective food products were placed in the respective bags.
- Observation Parameters: All sets were observed till the Control Sets were non-marketable with respect to- i. Percent physiological loss in weight (% PLW), ii. Visual changes in the food products through photographs and iii. Sensory evaluation using Ranking Test.
Table-2: Labelling of Test Products for Quantitative Analysis
No. |
Type of Product |
Labels |
1. |
Control |
Control-LDPE |
2. |
Control |
Control-NYLON |
3. |
Freshness Plus |
Freshness Plus-LDPE |
4. |
Freshness Plus |
Freshness Plus-NYLON |
5. |
Food Fresh |
Food Fresh-LDPE |
6. |
Food Fresh |
Food Fresh-NYLON |
7. |
Anti-ripening CL Bags |
AR-CL-Micro AR-CL-Macro |
8. |
Anti-ripening BR Bags |
AR-BR-Micro AR-BR-Macro |
9. |
Anti-ripening IO Bags |
AR-IO-Micro AR-IO-Macro |
Results and Discussion
- . Quantitative Testing
- Ethylene Concentration Fig-1 Ethylene Concentration in all Bags
As seen from Fig-1, ethylene concentration was lowest in all Macro-Perforated Bags – i.e. Freshness Plus-LDPE, AR-CL 1% – Macro LDPE, AR-BR 1% – Macro LDPE, AR-IO 1% – Macro LDPE followed by Food Fresh LDPE.
- Carbon Dioxide Concentration
B. Efficacy Testing
- Physiological Loss in Weight (% PLW)
- Freshness Plus Bags:
Fig-2 Carbon Dioxide Concentrations in all bags
Of all the Bags (Fig-2), the % CO2 in Food Fresh LDPE was the lowest at the end of 7 days followed by Food Fresh NYLON Bags. % CO2 in Freshness Plus NYLON & Halogen Micro Bags was at par at the end of the test period.
Fig-3-Physiological Weight loss in Pomegranate
- Lifeguard Bags:
Fig-4 Physiological Weight Loss in Mangoes
(Temperature 20.2- 26.8 ºC and 37-56 % RH)
As seen in Fig-3, at the end of 65 days, Freshness Plus showed only 6.82 % PLW as compared to 29.04 for Control.
- Anti-Ripening Halogen Micro Bags –
- As seen in Fig-5, PLW (%) of Bananas increased during storage but was found to be the lowest (0.90 %) when packed in AR-CL Micro Bags as against Control Bags (2.00 %) at the end of the storage period of 7 days.Fig-5 Physiological Weight Loss in Banana
- Visual Observation with Photographs
- Freshness Plus Bags:
Fig-6: Pomegranate in Freshness Plus
Control–Day 70 Freshness Plus–Day 70
Fig-6 shows that Pomegranate in Freshness Plus Bag was firm, glossy and marketable as compared to Control samples which showed shrivelling, loss of gloss and irregular texture on surface.
- LifeGuard Bags:
Fig-7: Mangoes in Lifeguard
Lifeguard-Day 17 Control –Day 17
As seen in Fig-7, Mangoes in Lifeguard Bags looked fresh, firm with uniform ripening pattern, attractive and acceptable as compared to Control.
c. Anti-Ripening Halogen Bags:
Fig-8: Banana in AR-CL Macro Bags
Control Bag-Day 2 AR-CL Bag – Day 2
As seen from Fig-8, Bananas in AR-CL Macro bags were marketable & semi-ripe as compared to those in Control Bags.
Conclusions
Freshness Plus and Lifeguard Bags are promising solutions for post-harvest packaging to curb the global wastage of fresh produce.
We have explored 1 new route of post-harvest preservation of Bananas in Anti-ripening Halogen Bags. The bags based on release agents of Chlorine may perform better as compared to those based on Bromine or Iodine. But the data presented here on other fresh produce needs more authentication and further research to confirm the efficacy of these new generation packaging.
References:
- FAO, 2014 Website (fao.org).
- L. Raje, S. Sherlekar, K. Ramakrishnan, V.C.Malshe, G. Subbalakshmi, Post Harvest Preservation of mangoes by controlled release agents and adsorbent, Acta Horticulturae 455; 5th International Mango Symposium (1996).
