Rheological Behavior of Tomato Fruits Affected By Various Loads Under Storage Conditions

Abstract: Rheological properties of fruits and vegetables are of interest to plant physiologists, horticulturalists, agricultural engineers and food engineers, due to different causes. the rheological properties are relevant to several aspects of the study of these materials, including the causes and extent of damage during harvesting, transport and storage; the human perception of product quality. The rheological constants of the four element Burgers model when tomatoes were subjected to various fixed loads (stresses) on the main dimensions of the fruits were investigated .The rheological constants, K 1 (instantaneous elasticity, N/mm), K 2 (retarded elasticity, N/mm), C 1 (free viscous element, N.min/mm and C 2 (retarded viscous element, N.min/mm) were decreased significantly with storage time

Vibration analysis influence during crisis transport of the quality of fresh fruit on food security

Mechanical damage of agriculture produce is a major problem in the harvest and post-harvest chain.  This damage could cause huge economic loss.  In addition, it could lead to serious food safety concerns.  Several cases of foodborne illness have been traced to poor or unsanitary postharvest practices.  Escherichia coli (E. coli) O157:H7, Salmonella, Shigella, Listeria, Cryptosporidium, Hepatitis, and Cyclospora are among the diseases and disease-causing organisms that have been associated with fresh fruits and vegetables.  Measurements of mechanical characteristics of agricultural products under different static and dynamic loads should help in predicting the type and magnitude of mechanical injuries which will help in minimizing losses and improve the safety the produce.  In the current study, we examined the parameters essential for fruit package processes.  Fruits were exposed to random excitation( is excited by combination of single- sinusoidal signal and a broad band stochastic single and compared to pure stochastic excitation) by using robust techniques EFDD enhanced frequency domain to harmonic excitation.  Six vibration modes were identified in the frequency range of 0-1.6 kHz by two techniques FDD & EFDD.  The paper-wrap and foam-net cushioning materials interaction is also studied.  Damage identification technique has been applied to determine the integrity of the structure.  Nearly all the examined fruit showed deterioration due to vibro-pressure and friction stresses mainly consisting of translucent or darkened bruises and streaks.  Results obtained from test without cushioning materials have been correlated with the package of paper-wrap cushioning materials and foam-net cushioning materials.     Keywords: vibration analysis, crisis transport, quality, damage, food safet