scholarly journals Impacts of Huanglongbing Symptom Severity on Fruit Detachment Force and Mechanical Properties of Sweet Oranges (Citrus sinensis)

HortScience ◽  
2016 ◽  
Vol 51 (4) ◽  
pp. 356-361 ◽  
Author(s):  
Hong Chen ◽  
Greg McCollum ◽  
Elizabeth Baldwin ◽  
Jinhe Bai

This study evaluated the effects of huanglongbing (HLB) symptom severity on fruit detachment force (FDF) and fruit mechanical properties in sweet oranges (Citrus sinensis) as indicators of potential HLB-influenced preharvest fruit drop and postharvest damage and breakdown. FDF for fruit from HLB-asymptomatic trees (AS) was substantially greater than for fruits from HLB-symptomatic trees or branches. Fruit hardness, resilience, springiness, and cohesiveness values, measured by texture profile analysis (TPA), represent various aspects of fruit firmness and recovery capacity once compressed, and were lower in HLB-symptomatic fruits in comparison with AS fruits. On the other hand, puncture force, toughness, and deformation values, measured by a puncture test and representing peel toughness, were higher in HLB-symptomatic fruits than in the AS fruits. The results indicate that fruits from severely HLB-symptomatic sweet orange trees are more likely to have problems with preharvest fruit drop, and postharvest pressure damage and breakdown, but may have less puncture damage in harvesting, transportation, packing, and juice processing.

2021 ◽  
Vol 8 ◽  
Author(s):  
Gabriela Nallely Trejo-Díaz ◽  
Miguel Ángel Martínez-Maldonado ◽  
Rocío M. Uresti-Marín ◽  
Gonzalo Velazquez ◽  
José Alberto Ramírez

Cooked crab meat subjected to a cutting process can aggregate again, forming weak gels. The objective of this work was to determine the effect of two mixing methods, combined with the addition of the microbial enzyme TGase (MTGase) on the mechanical and functional properties of gels from washed or unwashed blue crab (Callinectes sapidus) meat. Live crabs were obtained from Laguna Madre, Tamaulipas, Mexico, and cooked at 120°C for 20 min before hand-picking the meat from the shell. Cooked meat was processed by mixing and cut at temperatures of 25 or 60°C, without (control) or 0.5% of MTGase. Then cooked at 90°C for 15 min. Changes in texture profile analysis, percentage of extractable water, and color were evaluated. The mixing method at 60°C allowed increasing the textural properties of the gels, and the addition of MTGase significantly improved the mechanical properties. The results allowed stablishing a viable technique to obtain restructured gels from cooked crab meat with no need to extract the soluble compounds responsible for their distinctive odor and taste which often affect the mechanical properties.


1999 ◽  
Vol 5 (1) ◽  
pp. 79-87 ◽  
Author(s):  
M.J. Hernández ◽  
L. Durán ◽  
E. Costell

Fruit gels were prepared containing four levels (20, 40, 60 and 80%) of strawberry pulp, four levels (0.5, 0.7, 0.9 and 1.1 %) of hydrocolloids (kappa-carrageenan plus locust bean gum, 1:1) and two levels (0, 10%) of sucrose. Their mechanical properties were analyzed by compression (failure stress and failure strain) and by texture profile analysis, TPA (hardness, cohesiveness, springiness, adhesive ness, and chewiness). Addition of hydrocolloids produced expected increases in both stress and strain at failure. Sucrose increased failure stress but did not alter strain values. Increasing the pulp content from 20 to 80% resulted in a slight increase in stress and clearly lowered strain at failure. Fruit pulp addition produced increasing hardness, chewiness and adhesiveness values, and lowered cohesive ness and springiness. MANOVA analysis of TPA data showed that while gel hardness was mainly governed by hydrocolloid concentration, both cohesiveness and adhesiveness were clearly depen dent on the proportion of fruit pulp.


2005 ◽  
Vol 15 (4) ◽  
pp. 758-765 ◽  
Author(s):  
Jacqueline K. Burns ◽  
Richard S. Buker ◽  
Fritz M. Roka

An abscission agent [5-chloro-3-methyl-4-nitro-1H-pyrazole (CMNP)] was applied to `Hamlin' and `Valencia' orange (Citrus sinensis) trees at concentrations ranging from 0 to 500 ppm in a volume of 300 gal/acre. Four days after application, fruit were mechanically harvested with either a trunk shake-and-catch or a continuous canopy shake-and-catch system commercially used in Florida. Harvesting conditions were varied by limiting the actual trunk shake time of the trunk shaker to 2, 4, or 7 seconds, or by altering the ground speed of the canopy shaker (1.0, 1.5, or 2.0 mph). In general, increasing duration of shake and the application of CMNP increased percent mature fruit removal and decreased the amount of fruit remaining in the tree. Increasing CMNP concentration decreased fruit detachment force but increased post-spray fruit drop. Comparison of short duration shake times in CMNP-applied trees with trees harvested at longer durations either sprayed or not sprayed with CMNP indicated no significant difference in percent mature fruit removal. The results demonstrate that CMNP application increases harvesting capacity of trunk and canopy shakers by reducing time necessary to harvest each tree while maintaining high percent mature fruit removal.


2000 ◽  
Vol 125 (5) ◽  
pp. 547-552 ◽  
Author(s):  
Ulrich Hartmond ◽  
Rongcai Yuan ◽  
Jacqueline K. Burns ◽  
Angela Grant ◽  
Walter J. Kender

Methyl jasmonate (MJ) was tested as a potential abscission chemical to enhance mechanical harvest of `Hamlin' and `Valenica' orange [Citrus sinensis (L.) Osb.]. In field experiments, a solution of 1, 5, 10, 20, or 100 mm MJ was applied either as a stem wrap to individual fruit or as a spray to entire trees or canopy sectors. Solutions of 10, 20, and 100 mm MJ resulted in significant and consistent reduction of fruit detachment force and caused fruit drop within 7 to 10 days. Fruit loosening was preceded by an increase in the internal ethylene concentration of fruit similar to that of other experimental abscission compounds. While concentrations of 10 mm and less caused no or negligible phytotoxicity, solutions exceeding 10 mm MJ induced unacceptable levels of leaf abscission.


Author(s):  
N. Jonkers ◽  
J. A. W. van Dommelen ◽  
M. G. D. Geers

AbstractThe texture profile analysis test is an imitative test to determine texture properties of food, which quantify the consumer’s perception of eating food. The instrumental texture parameters obtained from this test depend on the specimen size and the nonstandardized test conditions. To overcome this problem, texture properties are here related to intrinsic mechanical properties, which are independent of the test conditions. Two types of materials are used to investigate the effect of viscoelasticity, plasticity and damage on the texture parameters for varying test conditions. Analytical relations between mechanical properties, test conditions, and the instrumental hardness, springiness, cohesiveness, and adhesiveness are determined. The hardness is obtained from the stiffness of the material, which is potentially rate-dependent, and the yield stress of a material in case of plasticity. The springiness is determined by the recoverable or irrecoverable strain in the material, which results from the mechanical properties in combination with the test conditions. Cohesiveness and springiness are found to be strongly related, unless structural damage is present in the material. Adhesiveness is only an indirect measure of the adhesion between the material and compression plate and depends on the test conditions and stiffness of the material. Finite element simulations reveal a decrease of hardness in case of a nonflat top surface, indicating the importance of geometrical effects.


Author(s):  
Mohd Muzamir Mahat ◽  
Awis Sukarni Mohmad Sabere ◽  
Saiful 'Arifin Shafiee ◽  
Mohd Azizi Nawawi ◽  
Hairul Hisham Hamzah ◽  
...  

The popularity of functional gummies has increased, which is evident from the growing line of functional gummies from almost every nutraceutical companies. Sensory evaluation serves the purpose of determining which brand of functional gummy would capture the largest market share. Texture profile analysis was used to determine the mechanical properties of functional gummies. The brands of functional gummies that came under the scope of this study were denoted as Brand A, B, C, D, E, F and G. Fourier Transform Infrared Spectroscopy was utilised to detect organic material and functional groups in the functional gummies. Texture profile analysis gave valuable insights into the gummies’ mechanical properties which are cohesiveness, springiness, hardness, gumminess, and chewiness. Amongst the gummies that were studied, Brand F gummy has the highest value of cohesiveness of 0.92. Brand A gummy has a high springiness value of 1.0. Brand B gummy possesses the highest value of hardness, gumminess and chewiness of 12 532.2 g, 7617.6 N, and 6256.8 J, respectively. Qualitative sensory evaluation reveals that Brand G gummy has the best aesthetic qualities in terms of colour and appearance. Brand B gummy tastes the best while brand A gummy claims the top spot for gumminess and chewiness. Overall, the respondents in this study preferred brand A gummy over other brands.


Foods ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 560
Author(s):  
Allah Bakhsh ◽  
Se-Jin Lee ◽  
Eun-Yeong Lee ◽  
Nahar Sabikun ◽  
Young-Hwa Hwang ◽  
...  

This study assessed the effects of Methylcellulose (MC) at different concentrations on plant-based meat analog (PBMA) patties, comprised of commercial texture vegetable protein (C-TVP) and textured isolate soy protein (T-ISP) as key ingredients, and compared to beef patty control. A significantly higher difference was observed in moisture content in control with increasing MC concentration than the C-TVP and T-ISP patties. However, protein varied significantly among three different protein sources, with control had higher protein content than PBMA patties. Crude fiber content recorded higher values in C-TVP as compared to control. Significantly lower pH values were recorded in control than C-TVP and T-ISP respectively. Regardless, with the addition of MC or ingredient PBMA and control patties tend to reduce lightness (L*) and redness (a*) value after cooking. Although control sample before cooking exhibits lighter and redder than PBMA patties (C-TVP and T-ISP). Likewise, water holding capacity (WHC) decreases as the concentration of MC increases (1.5–4%) in control and PBMA patties. Warner-Bratzler shear force (WBSF) and texture profile analysis (TPA), including hardness, chewiness, and gumminess of control, were significantly higher than C-TVP and T-ISP. Consequently, panelists’ in the sensory analysis presented that C-TVP patties containing 3% of MC had better sensory properties than T-ISP. Hence, PBMA patties with C-TVP and incorporation of 3% MC are considered ideal for manufacturing of meat analog as related to control (beef).


Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 266
Author(s):  
Shaked Eliyahu ◽  
Alexandra Galitsky ◽  
Esther Ritov ◽  
Havazelet Bianco-Peled

We developed and characterized a new hydrogel system based on the physical and chemical interactions of pectin partially modified with thiol groups and chitosan modified with acrylate end groups. Gelation occurred at high pectin thiol ratios, indicating that a low acrylated chitosan concentration in the hydrogel had a profound effect on the cross-linking. Turbidity, Fourier transform infrared spectroscopy, and free thiol determination analyses were performed to determine the relationships of the different bonds inside the gel. At low pH values below the pKa of chitosan, more electrostatic interactions were formed between opposite charges, but at high pH values, the Michael-type addition reaction between acrylate and thiol took place, creating harder hydrogels. Swelling experiments and Young’s modulus measurements were performed to study the structure and properties of the resultant hydrogels. The nanostructure was examined using small-angle X-ray scattering. The texture profile analysis showed a unique property of hydrogel adhesiveness. By implementing changes in the preparation procedure, we controlled the hydrogel properties. This hybrid hydrogel system can be a good candidate for a wide range of biomedical applications, such as a mucosal biomimetic surface for mucoadhesive testing.


Foods ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1368
Author(s):  
Marbie Alpos ◽  
Sze Ying Leong ◽  
Indrawati Oey

Legumes are typically soaked overnight to reduce antinutrients and then cooked prior to consumption. However, thermal processing can cause over-softening of legumes. This study aimed to determine the effect of calcium addition (0, 100, 300, and 500 ppm in the form of calcium chloride, CaCl2), starting from the overnight soaking step, in reducing the loss of firmness of black beans during thermal processing for up to 2 h. The impact of calcium addition on the in vitro starch and protein digestibility of cooked beans was also assessed. Two strategies of calcium addition were employed in this study: (Strategy 1/S1) beans were soaked and then cooked in the same CaCl2 solution, or (Strategy 2/S2) cooked in a freshly prepared CaCl2 solution after the calcium-containing soaking medium was discarded. Despite the texture degradation of black beans brought about by increasing the cooking time, texture profile analysis (TPA) revealed that their hardness, cohesiveness, springiness, chewiness, and resilience improved significantly (p < 0.05) with increasing calcium concentration. Interestingly, beans cooked for 2 h with 300 ppm CaCl2 shared similar hardness with beans cooked for 1 h without calcium addition. Starch and protein digestibility of calcium-treated beans generally improved with prolonged cooking. However, calcium-treated beans cooked for 1 h under S2 achieved a reduced texture loss and a lower starch digestibility than those beans treated in S1. A lower starch digestion could be desired as this reflects a slow rise in blood glucose levels. Findings from this result also showed that treating black beans with high level of CaCl2 (i.e., 500 ppm) was not necessary, otherwise this would limit protein digestibility of cooked black beans.


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