Toward a Circular Bioeconomy: Development of Pineapple Stem Starch Composite as a Plastic-Sheet Substitute for Single-Use Applications

Abstract

Plastic waste poses a significant challenge for the environment, particularly smaller plastic products that are often difficult to recycle or collect. In this study, we developed a fully biodegradable composite material from pineapple field waste that is suitable for small-sized plastic products that are difficult to recycle, such as bread clips. We utilized starch from waste pineapple stems, which is high in amylose content, as the matrix, and added glycerol and calcium carbonate as the plasticizer and filler, respectively, to improve the material’s moldability and hardness. We varied the amounts of glycerol (20–50% by weight) and calcium carbonate (0–30 wt.%) to produce composite samples with a wide range of mechanical properties. The tensile moduli were in the range of 45–1100 MPa, with tensile strengths of 2–17 MPa and an elongation at break of 10–50%. The resulting materials exhibited good water resistance and had lower water absorption (~30–60%) than other types of starch-based materials. Soil burial tests showed that the material completely disintegrated into particles smaller than 1 mm within 14 days. We also created a bread clip prototype to test the material’s ability to hold a filled bag tightly. The obtained results demonstrate the potential of using pineapple stem starch as a sustainable alternative to petroleum-based and biobased synthetic materials in small-sized plastic products while promoting a circular bioeconomy.

Development of Biodegradable Thermosetting Plastic Using Dialdehyde Pineapple Stem Starch

“…The stable points of water-absorbing ability are influenced by the presence of glycerol. Gradually increasing glycerol content leads to a decline in the maximum water absorption capacity, similar to observations previously reported for PSS film [ 33 ]. Other studies also note a decrease in water absorption capacity with higher plasticizer concentrations in carbohydrate-based plastics [ 72 , 73 , 74 ].…”

“…Similarly, in the case of thermosetting starch plastic, higher glycerol content enhances water insolubility, consistent with the proposed crosslinking structure as shown in Figure 9. Conversely, PSS-based plastics show a gradual increase in solubility (32% to 37%) with rising glycerol concentration, a trend noted in previous reports [33,75,77]. This behavior aligns with the findings of Basiak et al [78], where starch with higher amylose content exhibited a higher water solubility index.…”

“…This emergence may be attributed to the formation of amylose-glycerol complexes during starch plasticization under elevated temperature and pressure [ 67 ]. The degree of crystallinity experienced a decline with augmented glycerol content [ 33 ]. Analyzing thermosetting plastic starch from D30PSS, XRD diffractograms showcased broader and weaker amorphous peaks.…”

“…Moreover, films derived from PSS exhibit robust mechanical strength and exceptional water resistance, while retaining biodegradability [ 32 ]. The versatility of PSS-based materials has been explored in the creation of composite sheets [ 33 ], protective coatings for fruits and vegetables [ 34 ], rigid foam [ 35 ], water-based adhesives [ 36 ], food applications [ 37 , 38 ], and more. This renders PSS-based plastics appealing and presents an emerging challenge for their diverse applications.…”

Impact of Oil Addition on Physicochemical Properties and In Vitro Digestibility of Extruded Pineapple Stem Starch

“…In previous research, some studies have been conducted on the characterization [ 2 , 5 , 26 ] and modification of PSS [ 27 ], as well as on their applications in food [ 6 ] and non-food [ 28 , 29 ]. However, the study on the extrusion of PSS with oil additions has not yet been investigated.…”